#include<bits/stdc++.h>
using namespace std;
int n;
typedef long long ll;
ll C,k;
bool vis[5000505];
struct node{
	ll w,q;
}a[5000505];
int main(){
	scanf("%d%d%lld",&n,&k,&C);
	for(int i=1;i<=n;++i){
		scanf("%lld%lld",&a[i].w,&a[i].q);	
	}
	sort(a+1,a+1+n,[](node a,node b){return a.w<b.w;});
	int cnt=0,ans=0,tot=0;
	ll sum=0;
	priority_queue<ll,vector<ll>,greater<ll>>q;
	for(int i=1;i<=n;++i){
		if(sum+a[i].q<=C){
			sum+=a[i].q;++tot;++cnt;
			q.push(a[i].w-a[i].q);
		}
		if(tot>k){
			sum+=q.top();q.pop();--tot;
		}
		ans=max(ans,cnt);
		if(sum>C)break;
	}
	cout<<ans<<endl;
	return 0;
}