#include <algorithm>
#include <array>
#include <iostream>
#include <vector>

using namespace std;

void fix(vector<array<int, 2>>& v) {
  vector<array<int, 2>> nv;
  sort(v.begin(), v.end());
  for(auto [a, b]: v) {
    if(nv.empty() || nv.back()[1] < a-1) {
      nv.push_back({a, b});
    }
    else {
      nv.back()[1] = max(nv.back()[1], b);
    }
  }
  v.swap(nv);
}

int main() {
  int n, abase, bbase;
  cin >> n >> abase >> bbase;
  vector<vector<vector<array<int, 2>>>> dp(2);
  for(auto& x: dp) x.resize(n+1);
  dp[0][0].push_back({0, 0});
  for(int qq = 0; qq < n; qq++) {
    int src = qq%2;
    int dst = 1^src;
    dp[dst] = dp[src];
    int al, ar, bl, br;
    cin >> al >> ar >> bl >> br;
    al -= abase; ar -= abase;
    bl -= bbase; br -= bbase;
    if(ar < 0 || br < 0) continue;
    for(int i = max(al, 0); i <= min(ar, qq); i++) {
      for(auto [a, b]: dp[src][i]) {
        int nlhs = max(a, bl);
        int nrhs = min(b, br);
        if(nlhs <= nrhs) {
          dp[dst][i+1].push_back({nlhs, nrhs});
          dp[dst][i].push_back({nlhs+1, nrhs+1});
        }
      }
    }
    for(int i = 0; i <= qq+1; i++) fix(dp[dst][i]);
  }
  int ret = 0;
  int dst = (n%2);
  for(int i = 0; i <= n; i++) {
    if(dp[dst][i].size()) ret = max(ret, i + dp[dst][i].back()[1]);
  }
  cout << ret << "\n";
}