tj

#include<bits/stdc++.h>
using namespace std;
struct stu{
int high;
int liqi;
}t[11000];
bool cmp(stu x,stu y){
    return x.liqi<y.liqi;
}
int main(){
    int n,k,a,b,sum=0;
    cin>>n>>k>>a>>b;
    a+=b;
    for(int i=1;i<=n;i++){
        cin>>t[i].high>>t[i].liqi;
    }
    sort(t+1,t+n+1,cmp);
    for(int i=1;i<=n;i++){
        if(t[i].high<=a and t[i].liqi<=k){
            sum++;
            k-=t[i].liqi;
        }
    }cout<<sum;
    return 0;
}