跪求dalao!倒数第二个测试点过不了，RE，求教！！！

#include<iostream>
#include<algorithm>
using namespace std;
int x[5001],y[5001],can[5001];
int main()
{
	int n,s,a,b,ans=0,k=0;
	cin>>n>>s>>a>>b;
	for(int i=1;i<=n;i++)
	{	
		cin>>x[i]>>y[i];
		if(x[i]<=a+b)
		{
			k++;
			can[k]=y[i];
		}
	}
	sort(can+1,can+k+1);
	int i=1;
	while(s>=0)
	{
		s-=can[i];
		i++;
		ans++;
	}
	cout<<ans-1;
	return 0;
}