#include <iostream>
using namespace std;
const int N=1e5+5;
int n,k;
int h[N],w[N];
bool pan(int x)
{
int res=0;
for(int i=0;i<n;i++){
res+=(h[i]/x)*(w[i]/x);
}
if(res>=k) return true;
return false;
}
int main()
{
cin>>n>>k;
for(int i=0;i<n;i++)
cin>>h[i]>>w[i];
int l=1,r=1e5;
while(l<r){
int mid=l+r+1>>1;
if(pan(mid)) l=mid;
else r=mid-1;
}
cout<<r;
//cout << "Hello world!" << endl;
return 0;
}