#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cmath>
#define int long long
const int N=1e5+5;
using namespace std;
int n,k,a[N],b[N],c[N];
int w;
signed main(){
	cin>>n>>k;
	for(int i=1;i<=n;i++){
		cin>>a[i]>>b[i];		
		for(int j=1;j<=min(a[i],b[i]);j++){
				w=max(w,min(a[i],b[i]));			
			if(j==1)c[j]+=a[i]*b[i];
			else{
				int o=min(a[i],b[i]);
				int p=max(a[i],b[i]);
				c[j]+=(o/j)*(p/j);
			}
		}
	}
	for(int i=w;i>=1;--i){
		if(c[i]>=k){
			cout<<i;
			return 0;
		}
	}
	return 0;
}