#include <bits/stdc++.h>
#define int long long

using namespace std;

void solve () {
    int n, a, b;
    cin >> n >> a >> b;

    vector dp (n + 1, vector <int> (n + 1));
    dp[0][0] = 1;
    for (int w = 0; w < n; w ++) {
        int al, ar, bl, br;
        cin >> al >> ar >> bl >> br;

        al = max (al, a);
        ar = min (ar, a + n - 1);
        bl = max (bl, b);
        br = min (br, b + n - 1);
        al -= a;
        ar -= a;
        bl -= b;
        br -= b;

        auto ndp = dp;
        for (int i = al; i <= ar + 1; i ++) {
            for (int j = bl; j <= br + 1; j ++) {
                if (i == al && j == bl) {
                    continue;
                }
                if (i > al) {
                    ndp[i][j] |= dp[i - 1][j];
                }
                if (j > bl) {
                    ndp[i][j] |= dp[i][j - 1];
                }
            }
        }
        dp = move (ndp);
    }

    int maxx = 0;
    for (int i = 0; i <= n; i ++) {
        for (int j = 0; j <= n; j ++) {
            if (dp[i][j]) {
                maxx = max (maxx, i + j);
            }
        }
    }

    cout << maxx << '\n';
}

signed main () {
    ios::sync_with_stdio (false);
    cin.tie (nullptr);

    int T = 1;
    // cin >> T;

    while (T --) {
        solve ();
    }

    return 0;
}