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#include <algorithm>
#include <iostream>
#include <list>
#include <map>
#include <set>
#include <vector>
using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;

namespace {
  int compress(vector<int> const& v, int x)
  {
    auto it = lower_bound(v.begin(), v.end(), x);
    return it - v.begin();
  }

  struct Rect {
    int x1;
    int x2;
    int y1;
    int y2;

    Rect():
      x1{0}, x2{0}, y1{0}, y2{0}
    {
    }

    Rect(int x1_, int x2_, int y1_, int y2_):
      x1{x1_}, x2{x2_}, y1{y1_}, y2{y2_}
    {
    }

    explicit operator bool() const
    {
      return x1 < x2 && y1 < y2;
    }
  };

  Rect operator|(Rect const& a, Rect const& b)
  {
    return Rect{min(a.x1, b.x1), max(a.x2, b.x2), min(a.y1, b.y1), max(a.y2, b.y2)};
  }

  Rect operator&(Rect const& a, Rect const& b)
  {
    return Rect{max(a.x1, b.x1), min(a.x2, b.x2), max(a.y1, b.y1), min(a.y2, b.y2)};
  }

  Rect& operator|=(Rect& a, Rect const& b)
  {
    return a = a | b;
  }

  Rect& operator&=(Rect& a, Rect const& b)
  {
    return a = a & b;
  }

  template <typename OS>
  OS& operator<<(OS& s, Rect const& r)
  {
    return s << r.x1 << ' ' << r.x2 << ' ' << r.y1 << ' ' << r.y2;
  }

  bool operator<(Rect const& a, Rect const& b)
  {
    if (a.x1 != b.x1) return a.x1 < b.x1;
    if (a.x2 != b.x2) return a.x2 < b.x2;
    if (a.y1 != b.y1) return a.y1 < b.y1;
    if (a.y2 != b.y2) return a.y2 < b.y2;
    return false;
  }

  bool operator==(Rect const& a, Rect const& b)
  {
    return a.x1 == b.x1 && a.x2 == b.x2 && a.y1 == b.y1 && a.y2 == b.y2;
  }

  int round_up(int x)
  {
    int p = 1;
    while (p < x) p *= 2;
    return p;
  }

  struct Rect1DLess {
    bool operator()(Rect const& a, Rect const& b)
    {
      if (a.y1 != b.y1) return a.y1 < b.y1;
      return a < b;
    }
  };

  template <typename CI, typename I, typename C, typename A>
  class Rect1DUpdate {
    protected:
      void operator()(I it, CI end)
      {
        int m = (*it)->y2;
        if (it.get_l_child() != end) m = max(m, it.get_l_child().get_metadata());
        if (it.get_r_child() != end) m = max(m, it.get_r_child().get_metadata());
        const_cast<int&>(it.get_metadata()) = m;
      }

      virtual CI node_begin() const = 0;

      virtual CI node_end() const = 0;

      virtual ~Rect1DUpdate()
      {
      }

    public:
      typedef int metadata_type;

      bool query(Rect const& r, Rect& res)
      {
        CI it = node_begin();
        CI end = node_end();
        while (it != end) {
          if (r.y2 >= (*it)->y1 && r.y1 <= (*it)->y2) {
            res = **it;
            return true;
          }
          if (it.get_l_child() != end && it.get_l_child().get_metadata() >= r.y1) {
            it = it.get_l_child();
          } else {
            it = it.get_r_child();
          }
        }
        return false;
      }
  };

  class Rects {
    private:
      typedef tree<Rect, null_mapped_type, Rect1DLess, rb_tree_tag, Rect1DUpdate> lower;

      int m;
      vector<lower> all;
      vector<lower> any;

    public:
      Rects(int m_):
        m(round_up(m_)), all(2*m), any(2*m)
      {
      }

      void add(Rect const& r)
      {
        int a = m + r.x1;
        int b = m + r.x2;
        all[a].insert(r);
        all[b].insert(r);
        while (a/2 != b/2) {
          if (a % 2 == 0) all[a+1].insert(r);
          if (b % 2 == 1) all[b-1].insert(r);
          a /= 2;
          b /= 2;
          any[a].insert(r);
          any[b].insert(r);
        }
        while (a/2 > 0) {
          a /= 2;
          any[a].insert(r);
        }
      }

      void remove(Rect const& r)
      {
        int a = m + r.x1;
        int b = m + r.x2;
        all[a].erase(all[a].find(r));
        all[b].erase(all[b].find(r));
        while (a/2 != b/2) {
          if (a % 2 == 0) all[a+1].erase(all[a+1].find(r));
          if (b % 2 == 1) all[b-1].erase(all[b-1].find(r));
          a /= 2;
          b /= 2;
          any[a].erase(any[a].find(r));
          any[b].erase(any[b].find(r));
        }
        while (a/2 > 0) {
          a /= 2;
          any[a].erase(any[a].find(r));
        }
      }

      bool query(Rect const& r, Rect& res)
      {
        int a = m + r.x1;
        int b = m + r.x2;
        if (all[a].query(r, res)) return true;
        if (all[b].query(r, res)) return true;
        while (a/2 != b/2) {
          if (a % 2 == 0) {
            if (any[a+1].query(r, res)) return true;
            if (all[a+1].query(r, res)) return true;
          }
          if (b % 2 == 1) {
            if (any[b-1].query(r, res)) return true;
            if (all[b-1].query(r, res)) return true;
          }
          a /= 2;
          b /= 2;
          if (all[a].query(r, res)) return true;
          if (all[b].query(r, res)) return true;
        }
        while (a/2 > 0) {
          a /= 2;
          if (all[a].query(r, res)) return true;
        }
        return false;
      }
  };

  set<Rect> reduce(vector<Rect> const& rects, int mx)
  {
    set<Rect> res;
    Rects cur{mx};
    for (auto r: rects) {
      Rect s;
      while (cur.query(r, s)) {
        r |= s;
        cur.remove(s);
        res.erase(s);
      }
      res.insert(r);
      cur.add(r);
    }
    return res;
  }
}

int main()
{
  iostream::sync_with_stdio(false);
  cin.tie(NULL);

  int n;
  cin >> n;

  vector<Rect> rects;
  vector<int> xs;
  vector<int> ys;
  for (int i = 0; i < n; ++i) {
    int x1, x2, y1, y2;
    cin >> x1 >> x2 >> y1 >> y2;
    x1 *= 2; ++x1;
    y1 *= 2; ++y1;
    x2 *= 2;
    y2 *= 2;
    rects.push_back(Rect{x1, x2, y1, y2});
    xs.push_back(x1);
    xs.push_back(x2);
    ys.push_back(y1);
    ys.push_back(y2);
  }

  sort(xs.begin(), xs.end());
  xs.erase(unique(xs.begin(), xs.end()), xs.end());
  sort(ys.begin(), ys.end());
  ys.erase(unique(ys.begin(), ys.end()), ys.end());

  for (auto& rect: rects) {
    rect.x1 = compress(xs, rect.x1);
    rect.x2 = compress(xs, rect.x2);
    rect.y1 = compress(ys, rect.y1);
    rect.y2 = compress(ys, rect.y2);
  }

  auto res = reduce(rects, xs.size());

  cout << res.size() << '\n';
  for (auto const& rect: res) {
    cout << xs[rect.x1]/2 << ' ' << xs[rect.x2]/2 << ' ';
    cout << ys[rect.y1]/2 << ' ' << ys[rect.y2]/2 << '\n';
  }

  return 0;
}