//2. 分巧克力
//https://www.lanqiao.cn/problems/99/learning/?page=1&first_category_id=1&difficulty=20&second_category_id=3
//二分
#include <bits/stdc++.h>

#define int long long

using namespace std;

const int N = 1e5+10;

int n;//巧克力个数
int k;//小朋友个数
int h[N], w[N];//长和宽

bool solve(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;
}

signed main()
{
  // 请在此输入您的代码
  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-l+1 >>1);//找右边界
    if(solve(mid)) l = mid;
    else r = mid-1;
  } 

  cout<<r<<endl;

  return 0;
}