为啥只有40分

#include<bits/stdc++.h>
using namespace std;
struct apple{
    int high, li;
}app[5005];
int cnt, b, a, n, s;
bool cmp(apple A, apple B)
{
    return A.high > B.high;
}
int main()
{
    cin >> n >> s >> a >> b;
    for(int i = 1 ; i <= n; i++)
        cin >> app[i].high >> app[i].li;
    sort (app + 1, app + n + 1, cmp);
    for(int i = 1 ; i <= n ; i++)
    {
        if(s <= app[i].li)break;
        if(a + b >= app[i].high)
        {
            cnt ++;
            s -= app[i].li;
        }
        else
            break;
    }
    cout << cnt << endl;
    return 0;
}