#include <bits/stdc++.h>

using namespace std;

const int N = 5005;

set<int> S[N], z[N];

signed main() {
    int n, p, q; scanf("%d%d%d", &n, &p, &q);
    S[0].insert(0), z[0].insert(0);
    for (int i = 1; i <= n; ++i) {
        int a, b, c, d; scanf("%d%d%d%d", &a, &b, &c, &d);
        a -= p, b -= p, c -= q, d -= q;
        for (int j = a; j < i && j <= d; ++j) {
            set<int>::iterator it = z[j].lower_bound(c);
            vector<int> rm;
            vector< pair<int, int> > ad;
            while (it != z[j].end() && *it <= d) {
                rm.push_back(*it);
                if (!S[j].count(*it + 1)) ad.push_back({j, *it + 1});
                if (!S[j + 1].count(*it)) ad.push_back({j + 1, *it});
                ++it;
            }
            for (auto x : rm) z[j].erase(x);
            for (auto [x, y] : ad) S[x].insert(y), z[x].insert(y);
        }
    }
    int res = 0;
    for (int i = 0; i <= n; ++i) {
        if (!S[i].empty()) res = max(res, i + *--S[i].end());
    }
    printf("%d\n", res);
    return 0;
}