#include<bits/stdc++.h>
using namespace std;
#define V vector
#define pb push_back
#define fi first
#define se second
#define lb lower_bound
#define all0(x) (x).begin(), (x).end()
#define all1(x) (x).begin() + 1, (x).end()

typedef pair<int, int> pi;
typedef long long LL;
typedef double db;

const int INF = 2e9 + 10;
const LL INFLL = 8e18 + 10;


void solve() {
    int n; cin >> n;
    int a, b; cin >> a >> b;
    V<set<int>> st(n + 1);
    V<V<int>> used(n + 1, V<int>(n + 1));
    used[0][0] = 1;
    st[0].insert(0);
    for(int i = 1; i <= n; i++) {
        int a0, a1, b0, b1; cin >> a0 >> a1 >> b0 >> b1;
        a0 -= a, a1 -= a, b0 -= b, b1 -= b;
        for(int i = max(a0, 0); i <= min(n, a1); i++) {
            auto it = st[i].lb(b0);
            while(it != st[i].end() && *it <= b1) {
                if(!used[i][*it + 1]) st[i].insert(*it + 1), used[i][*it + 1] = 1;
                if(!used[i + 1][*it]) st[i + 1].insert(*it), used[i + 1][*it] = 1;
                it = st[i].erase(it);
            }
        }
    }
    int ans = 0;
    for(int i = 0; i <= n; i++) {
        for(int j = 0; j <= n; j++) {
            if(used[i][j]) ans = max(ans, i + j);
        }
    }
    cout << ans << endl;
}

int main() {
    solve();
}