#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,s,a,b,cnt;
	int x[5005];
	int y[5005];
	int v[5005]={0};
	cin>>n>>s>>a>>b;
	for(int i=1;i<=n;i++){
		cin>>x[i]>>y[i];
	}
	for(int i=1;i<=n;i++){
		int minn=1e9;
		int p;
	for(int j=1;j<=n;j++){
		if(x[j] <= a+b && v[j] == 0 && y[j] < minn){
			minn=y[j];
			p=j;
		}
	}
	v[p]=1;
	if(s>=minn){
	s-=minn;
	cnt++;	
	}
	else{
		cout<<cnt;
		return 0;
}
}
	return 0;
}

**** 谁来帮我看看哪里错了，谢谢！****