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#include <cstdio>
#include <algorithm>
#include <set>
#include <cmath>

using namespace std;

#define D(x)
#define E(x)
#define S(x)

#define INF 1000000001
//int TREE_SIZE;

struct Point{
    int id;
    int x,y;
    Point(){}
};

struct Rectangle{
    Point p1, p2;

    Rectangle(){}
    Rectangle(const Point& p1, const Point& p2): p1(p1), p2(p2){}
};

struct Query{
    int minX, minY;
    int maxX, maxY;
    Query(){}
    Query(int minX, int minY, int maxX, int maxY)
        : minX(minX), minY(minY), maxX(maxX), maxY(maxY){}
    Query(const Rectangle& rc){
        minX = rc.p1.x;
        minY = rc.p1.y;
        maxX = rc.p2.x;
        maxY = rc.p2.y;
    }
};

struct PointByX{
    bool operator()(const Point& lhs, const Point& rhs){
        if(lhs.x != rhs.x)
            return lhs.x < rhs.x;
        if(lhs.id != rhs.id)
            return lhs.id < rhs.id;
      //  if(lhs.y != rhs.y)
            return lhs.y < rhs.y;

    }
};

bool comparePointByX(const Point& lhs, const Point& rhs){
    if(lhs.x != rhs.x)
        return lhs.x < rhs.x;
    if(lhs.id != rhs.id)
        return lhs.id < rhs.id;
    //if(lhs.y != rhs.y)
        return lhs.y < rhs.y;
}

struct PointByY{
    bool operator()(const Point& lhs, const Point& rhs){
        if(lhs.y != rhs.y)
            return lhs.y < rhs.y;
        if(lhs.id != rhs.id)
            return lhs.id < rhs.id;
        //if(lhs.x != rhs.x)
            return lhs.x < rhs.x;
    }
};

bool comparePointByY(const Point& lhs, const Point& rhs){
    if(lhs.y != rhs.y)
        return lhs.y < rhs.y;
    if(lhs.id != rhs.id)
        return lhs.id < rhs.id;
    //if(lhs.x != rhs.x)
        return lhs.x < rhs.x;

}

inline int leftSon(const int index){
    return 2*index+1;
}
inline int rightSon(const int index){
    return 2*index+2;
}
inline int parent(const int index){
    return (index-1)/2;
}

struct SetPointer{
    int index;
    int x;

    SetPointer(){}
    SetPointer(int index, int x) : index(index), x(x){}

    bool operator<(const SetPointer& rhs) const{
        if(x != rhs.x)
            return x < rhs.x;
        return index < rhs.index;

    }
};

struct SetTree{
    set<Point, PointByY> *tree;//[TREE_SIZE*2];
    set<SetPointer> pointers;
    int TREE_SIZE;
    SetTree(Point * points, int numberOfPoints, int treeSize) : TREE_SIZE(treeSize){
        tree = new set<Point, PointByY>[TREE_SIZE*2];
        sort(points, points+numberOfPoints, comparePointByX);
        int pointsPerSet = ceil((float)numberOfPoints / TREE_SIZE);
        for(int i = TREE_SIZE-1; i<2*TREE_SIZE-1; i++){
            int currentIndex = (i-TREE_SIZE+1)*pointsPerSet;
            if(currentIndex >= numberOfPoints) break;

            pointers.insert(SetPointer(i, points[currentIndex].x));
            E(printf("%d %d\n", currentIndex, points[currentIndex].x));

            int start = currentIndex;
            int end = min(currentIndex+pointsPerSet, numberOfPoints);
            if(start!=end){
                //printf("%d %d\n", start, end);
                sort(points+start, points+end, comparePointByY);
                tree[i] = set<Point, PointByY>(points + start, points + end);

                for(int j=0; j<pointsPerSet && currentIndex+j<numberOfPoints; j++){
                     //tree[i].insert(points[currentIndex+j]);

                    insert(points[currentIndex+j], i);
                }
            }
        }
    }
    ~SetTree(){
        delete []tree;
    }

    void printTree() const{
        for(int i=0; i<TREE_SIZE*2; i++){
            for(const Point& p : tree[i]){
                printf("|%d %d %d|", p.x, p.y, p.id);
                //if(p.id == 0) printf("ZERO!\n\n\n\n");
            }
            printf("\n");
        }
    }

    set<int> search(const Query& query) const{
        auto itLeft = pointers.lower_bound(SetPointer(-1, query.minX));
        while((itLeft == pointers.end()) ||
                (itLeft->x >= query.minX && itLeft != pointers.begin())) itLeft--;

        auto itRight = pointers.lower_bound(SetPointer(INF, query.maxX));
        if(itRight == pointers.end() ||
                (itRight->x > query.maxX && itRight != pointers.begin())) itRight--;


        int leftId = itLeft->index;
        int rightId = itRight->index;
        D(printf("left: %d, right: %d\n", leftId, rightId));

        set<int> points;
        if(leftId != rightId) searchInBucket(query, tree[leftId], points);
        searchInBucket(query, tree[rightId], points);
        while(leftId + 1 < rightId){
            if(leftId%2 == 1) searchInBucket(query, tree[leftId+1], points);
            leftId = parent(leftId);

            if(rightId%2 == 0) searchInBucket(query, tree[rightId-1], points);
            rightId = parent(rightId);
        }
        return points;
    }

   void deletePoint(const Point& point) const{

        auto itLeft = pointers.lower_bound(SetPointer(-1, point.x));
        while((itLeft == pointers.end()) ||
                (itLeft->x >= point.x && itLeft != pointers.begin())) itLeft--;
        //E(printf("itleftX: %d\n", itLeft->x));
        while(itLeft != pointers.end() && itLeft->x <= point.x){
            auto& ySet = tree[itLeft->index];
            auto it = ySet.find(point);
            if(it != ySet.end()){
                ySet.erase(it);
                int index = itLeft->index;
                while(index > 0){
                    index = parent(index);
                    tree[index].erase(point);
                }
                return;
            }
            itLeft++;
        }
        E(printf("%d %d\n", point.x, point.y));
        E(printTree());
        //assert(false);
   }

   void insertPoint(const Point& point) const{
       auto itLeft = pointers.lower_bound(SetPointer(-1, point.x));
       if((itLeft == pointers.end()) ||
               (itLeft->x > point.x && itLeft != pointers.begin())) itLeft--;
       auto& ySet = tree[itLeft->index];
       ySet.insert(point);

       int index = itLeft->index;

       while(index > 0){
           index = parent(index);
           tree[index].insert(point);
       }
   }

private:
    void searchInBucket(const Query& query, set<Point, PointByY>& src, set<int>& points) const{
        Point startPoint;
        startPoint.y = query.minY;
        startPoint.id = -1;
        auto it = src.lower_bound(startPoint);

        int minX = query.minX;
        int maxX = query.maxX;
        int maxY = query.maxY;

        while(it != src.end() && it->y <= maxY){
            int x = it->x;
            //(printf("@%dx%dy%d@", it->id, it->x, it->y));
            if(x >= minX && x <= maxX) points.insert(it->id);
            it++;
        }
    }

    inline void insert(const Point& point, int index) const{
        //tree[index].insert(point);
        do{
            index = parent(index);
            tree[index].insert(point);
        }while(index > 0);
    }
};

inline bool intersect(const Rectangle& r1, const Rectangle& r2){
   return (r1.p1.x < r2.p2.x && r1.p2.x > r2.p1.x &&
        r1.p1.y < r2.p2.y && r1.p2.y > r2.p1.y);
}

void maximize(Rectangle& mRec, const Rectangle& addRec){
    if(addRec.p1.x < mRec.p1.x) mRec.p1.x = addRec.p1.x;
    if(addRec.p1.y < mRec.p1.y) mRec.p1.y = addRec.p1.y;
    if(addRec.p2.x > mRec.p2.x) mRec.p2.x = addRec.p2.x;
    if(addRec.p2.y > mRec.p2.y) mRec.p2.y = addRec.p2.y;
}

void deleteAllPointsFromRectangle(const SetTree* tree, const Rectangle& rec){
    tree->deletePoint(rec.p1);
    tree->deletePoint(rec.p2);

    Point p3 = rec.p1;
    p3.x = rec.p2.x;

    tree->deletePoint(p3);

    Point p4 = rec.p2;
    p4.x = rec.p1.x;
    tree->deletePoint(p4);
}

void putAllPointsFromRectangle(const SetTree* tree, const Rectangle& rec){
    tree->insertPoint(rec.p1);
    tree->insertPoint(rec.p2);

    Point p3 = rec.p1;
    p3.x = rec.p2.x;

    tree->insertPoint(p3);

    Point p4 = rec.p2;
    p4.x = rec.p1.x;
    tree->insertPoint(p4);
}

bool lexiOrder(const Rectangle& lhs, const Rectangle& rhs){
    if(lhs.p1.x != rhs.p1.x) return lhs.p1.x < rhs.p1.x;
    if(lhs.p2.x != rhs.p2.x) return lhs.p2.x < rhs.p2.x;
    if(lhs.p1.y != rhs.p1.y) return lhs.p1.y < rhs.p1.y;
    return lhs.p2.y < rhs.p2.y;
}


//-------------------------------------------------------------------------

struct XSeg{
    Point p;
    int height;
    bool opening;

    XSeg(){}
    XSeg(Point p, int height, bool opening): p(p), height(height), opening(opening){}
    XSeg(const Rectangle &rec, bool opening): opening(opening){
        p = rec.p1;
        if(!opening) p.x = rec.p2.x;
        height = rec.p2.y - rec.p1.y;
    }

    bool operator<(const XSeg& rhs) const{
        if(this->p.x != rhs.p.x)
            return p.x < rhs.p.x;
        if(opening != rhs.opening)
            return opening < rhs.opening;
        return p.id < rhs.p.id;
    }
};

struct YSeg{
    int id;
    int y;
    int height;

    YSeg(){}
    YSeg(int id, int y, int height): id(id), y(y), height(height){}
    YSeg(const XSeg& seg){
        id = seg.p.id;
        y = seg.p.y;
        height = seg.height;
    }

    bool operator<(const YSeg& rhs) const{
        if(y != rhs.y)
            return y < rhs.y;
        return id < rhs.id;
    }

};

void prepare(Rectangle* rects, int n){
    set<YSeg> sweep;
    set<XSeg> sweepSrc;

    for(int i=0; i<n; i++){
        sweepSrc.insert(XSeg(rects[i], true));
        sweepSrc.insert(XSeg(rects[i], false));
    }
    //sort(sweepSrc.begin(), sweepSrc.end());

    bool changed = false;
    for(auto srcIt = sweepSrc.begin(); srcIt != sweepSrc.end(); ){

        changed = false;
        S(printf("X%d|", srcIt->p.x));
        if(srcIt->opening){
            S(printf("O"));
            XSeg src = XSeg(rects[srcIt->p.id], true);
            auto it = sweep.lower_bound(YSeg(src));
            Rectangle beforeMax = rects[src.p.id];
            auto itLow = it;
            S(if(it== sweep.begin()) printf("BEGIN"));
            if(it != sweep.begin()){
                it--;
                while(it->y + it->height > src.p.y){
                     S(printf("PRZECIECIE DOL!"));
                    maximize(rects[src.p.id], rects[it->id]);
                    changed = true;
                    src = XSeg(rects[src.p.id], true);
                    auto lastIt = it;
                    if(it != sweep.begin()) it--;
                    else{
                        sweep.erase(lastIt);
                        break;
                    }
                    sweep.erase(lastIt);

                }
            }
            it = itLow;
            while(it != sweep.end() && it->y < src.p.y + src.height){
                S(printf("PRZECIECIE!%d|", rects[it->id].p1.x));
                maximize(rects[src.p.id], rects[it->id]);
                changed = true;
                src = XSeg(rects[src.p.id], true);
                auto lastIt = it;
                it++;
                sweep.erase(lastIt);
            }


            //}else{

                sweepSrc.erase(XSeg(beforeMax,false));
                sweepSrc.insert(XSeg(rects[src.p.id], false));
            if(!changed){
                sweep.insert(YSeg(XSeg(rects[src.p.id], true)));
            }
            //}

        }
        else{
            sweep.erase(YSeg(*srcIt));

        }
        if(!changed) srcIt++;
        S(printf("\n"));
    }


}
//--------------------------------------------------------------------------

int main(){
    int n;
    scanf("%d", &n);
    Point* points = new Point[n*4];
    Rectangle* rects = new Rectangle[n];

    for(int i=0 ;i<n; i++){
        scanf("%d%d%d%d", &rects[i].p1.x, &rects[i].p2.x, &rects[i].p1.y, &rects[i].p2.y);
        rects[i].p1.id = rects[i].p2.id = i;

    }
    prepare(rects, n);

    for(int i=0; i<n; i++){
        int i4 = i*4;

        points[i4] = rects[i].p1;
        points[i4+1] = rects[i].p1;
        points[i4+1].x = rects[i].p2.x;

        points[i4+2] = rects[i].p2;
        points[i4+3] = rects[i].p2;
        points[i4+3].x = rects[i].p1.x;
    }

    SetTree* tree = new SetTree(points, n*4, 2048);

    for(int i=0; i<n; i++){
        bool change = false;
        Rectangle mainRec = rects[i];
        if(mainRec.p1.id == -1) continue;

        set<int> inArea = tree->search(Query(rects[i]));
        for(int recId: inArea){
            if(recId == i) continue;
            D(printf("Y%d,%d ", i, recId));
            Rectangle addRec = rects[recId];
            D(if(addRec.p1.id == -1){ printf("YMCA"); });

            if(intersect(mainRec, addRec))
            {
                change = true;
                D(printf("X"));
                maximize(mainRec, addRec);

                //E(printf("DELETE %d\n", addRec.p1.id));
                deleteAllPointsFromRectangle(tree, addRec);
                rects[recId].p1.id = -1;
            }
        }
        if(change){
            //E(printf("DELETEX %d\n", rects[i].p1.id));
            deleteAllPointsFromRectangle(tree, rects[i]);
            putAllPointsFromRectangle(tree, mainRec);
            rects[i] = mainRec;
            i--;
        }

    }
    //delete tree;

    vector<Rectangle> result;
    for(int i=0; i<n; i++){
        Rectangle rec = rects[i];

        if(rec.p1.id == -1) continue;

        result.push_back(rec);
        D(printf("%d %d %d %d\n", rec.p1.x, rec.p2.x, rec.p1.y, rec.p2.y));
    }
    sort(result.begin(), result.end(), lexiOrder);

    printf("%d\n", (int)result.size());
    for(const Rectangle & rec: result){
        printf("%d %d %d %d\n", rec.p1.x, rec.p2.x, rec.p1.y, rec.p2.y);
    }

    //delete[] points;
    //delete[] rects;
    return 0;
}