2，3，5RE，40分，求助

#include<bits/stdc++.h>
using namespace std;

struct k{int x,y;}qq[5008];
bool kk(k c,k d){
if(c.y<d.y)return 1;}
int main(){
int n,s,a,b,sum=0;
cin>>n>>s>>a>>b;
for(int i=0;i<n;i++){cin>>qq[i].x>>qq[i].y;}
sort(qq,qq+n,kk);
for(int i=0;i<n;i++){
if(qq[i].x>a+b)continue;
if(qq[i].x<=a+b){
	if(s>=qq[i].y){sum++;s-=qq[i].y;}
	else break;}}
cout<<sum;
return 0;}