#include<bits/stdc++.h>
using namespace std;
int a[5005],n,s,b[5005],aa,bb,sum,c[5005];
int main(){
	cin>>n>>s;
    for(int i=1;i<=n;i++){
		cin>>a[i]>>b[i];
		c[i]=-1;
	}
    cin>>aa>>bb;
    bb+=aa;
    for(int i=1;i<=n;i++){
		if(a[i]<=bb){
			c[i]=b[i];
		}
	}
	sort(c+1,c+1+n);
	for(int i=1;i<=n;i++){
		if(c[i]!=-1&&s-c[i]>=0){
			s-=c[i];
			sum++;
		}else break;
	}
	cout<<sum;
    return 0;
}

20分只对了#4