#include<bits/stdc++.h>
#define int long long
#define N 100000+5
using namespace std;
struct node{
	int atk,hp;
	int htk;
};
bool cmp(node a,node b){
	return a.htk>b.htk;
}
node a[N];
int s[N],c[N];
main(){
	int n,atk,hp;
	cin>>n;
	cin>>atk>>hp;
	for(int i=1;i<=n;i++){
		cin>>a[i].atk>>a[i].hp;
	}
	sort(a+1,a+n+1,cmp);
	for(int i=1;i<=n;i++){
		if(a[i].hp%atk==0)a[i].htk=a[i].hp/atk*a[i].atk;
		else a[i].htk=(a[i].hp/atk+1)*a[i].atk;
		s[i]=s[i-1]+a[i].htk;
		c[i]=c[i-1]+s[i];
		//cout<<c[i]<<endl;
		if(c[i]>=hp){
			cout<<i<<endl;
			return 0;
		}
	}
	cout<<"Fail";
	return 0;
}