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#include <stdio.h>
#include <set>
#include <tuple>
using namespace std;

namespace {

typedef int I;
typedef tuple<I, I, I, I> P;//x1, x2, y1, y2
typedef set<P> Set;
typedef Set::iterator Iter;

I N;
Set points;

bool inflate(const P& p, I& x1, I& x2, I& y1, I& y2) {
  if (get<1>(p) <= x1 || x2 <= get<0>(p) || get<3>(p) <= y1 || y2 <= get<2>(p))
    return false;
  x1 = min(get<0>(p), x1);
  x2 = max(get<1>(p), x2);
  y1 = min(get<2>(p), y1);
  y2 = max(get<3>(p), y2);
  return true;
}

void insert(I x1, I x2, I y1, I y2) {
  bool wasInflated;
  do {
    wasInflated = false;
    for (Iter it = points.begin(); it != points.end();) {
      if (inflate(*it, x1, x2, y1, y2)) {
        it = points.erase(it);
        wasInflated = true;
      } else {
        ++it;
      }
    }
  } while (wasInflated);
  points.insert(P(x1, x2, y1, y2));
}

} //namespace

int main() {
  scanf("%d", &N);
  for (I n=0; n<N; ++n) {
    I x1, x2, y1, y2;
    scanf("%d %d %d %d", &x1, &x2, &y1, &y2);
    insert(x1, x2, y1, y2);
  }
  printf("%d\n", (int)points.size());
  for(const P& p : points) {
    printf("%d %d %d %d\n", get<0>(p), get<1>(p), get<2>(p), get<3>(p));
  }
  return 0;
}