https://www.acwing.com/problem/content/1229/

#include<bits/stdc++.h>
using namespace std;
const int N= 1e5+7;
int h[N],w[N];
int n,k;
bool check(int ans)
{
    int  cnt=0;
    for( int i=0;i<n;i++){
     cnt+=(h[i]/ans)* (w[i]/ans);

    //cnt+=s/(ans*ans);

    }
    return cnt>=k;
}
int main()
{
    cin>>n>>k;
    int ma=0;
    for(int i=0;i<n;i++)
    {
        scanf("%d%d",&h[i],&w[i]);
        ma=(max(h[i],ma),max(w[i],ma));
    }
    int r=ma,l=0;
    //int mid=(r+n)/2;
    while (l < r)
    {
        int mid = l + r + 1 >> 1;
        if (check(mid)) l = mid;
        else r = mid - 1;
    }
  // cout<<check(1361)<<endl;
    cout<<l<<endl;
    return 0;
}