#include<bits/stdc++.h>
using namespace std;
int main()
{
	int n,s;
	int a,b;
	int x,y;
	int cnt;
	cin>>n>>s;
	cin>>a>>b;
	int ab=a+b;
	for(int i=0;i<=n;i++)
	{
		cin>>x>>y;
		if(s>=0)
		{
			if(ab>=x)
			{
				s=s-y;
				cnt++;
			}
		}
		else continue;
	}
	cout<<cnt;
}