#include <bits/stdc++.h>

using i64 = long long;
using u64 = unsigned long long;

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

    int n, i0, t0;
    std::cin >> n >> i0 >> t0;

    std::vector <int> l(n + 1, 0), r(n + 1, -1);
    l[0] = r[0] = t0;
    for(int i = 0; i < n; i++) {
        int il, ir, tl, tr;
        std::cin >> il >> ir >> tl >> tr;

        for(int j = i; j >= 0; j--) {
            if(il <= i0 + j && i0 + j <= ir) {
                int L = std::max(l[j], tl);
                int R = std::min(r[j], tr);
                if(L <= R) {
                    r[j] = std::max(r[j], R + 1);
                    if(r[j + 1] < l[j + 1]) {
                        l[j + 1] = L;
                        r[j + 1] = R;
                    } else {
                        l[j + 1] = std::min(l[j + 1], L);
                        r[j + 1] = std::min(r[j + 1], R);
                    }
                }
            }
        }
    }

    int ans = 0;
    for(int j = 0; j <= n; j++) {
        if(l[j] <= r[j]) {
            ans = std::max(ans, j + r[j] - t0);
        }
    }

    std::cout << ans << '\n';

    return 0;
}