样例输入输出都对，结果20分……

#include <bits/stdc++.h>
using namespace std;
int main(){
    int n,s,a,b,xi,yi,sum;
    cin>>n>>s;
    cin>>a>>b;
    for(int i=0;i<n;i++){
        cin>>xi>>yi;
        if(xi<=a+b&&s-yi>=0){
            sum+=1;
            s-=yi;
        }
    }
    cout<<sum<<endl; 
    return 0;
}