不知道怎么对的

#include<bits/stdc++.h>
#define int long long
using namespace std;
struct apple {
    int s, h;
} ap[5010];
int n, s, a, b, ans;
bool cmp(apple a, apple b) {
    return a.s < b.s;
}
signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    cin >> n >> s >> a >> b;
    a += b;
    for (int i = 1; i <= n; i++)cin >> ap[i].h >> ap[i].s;
    sort(ap + 1, ap + n + 1, cmp);
    for (int i = 1; i <= n; i++) {
        if (s < 0)break;
        if (a >= ap[i].h)s -= ap[i].s, ans++;
    }
    cout << max(0ll, ans - 1);
    return 0;
}