https://www.acwing.com/problem/content/1229/
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<iostream>
using namespace std;
int n, k;
const int N = 1e5 + 10;
int h[N], w[N];
bool check(int mid)
{
int res = 0;
for (int i = 0; i < n; i++)
{
res += (h[i] / mid) * (w[i] / mid);
if (res >= k)return 1;
}
return 0;
}
int main()
{
cin >> n >> k;
for (int i = 0; i < n; i++)scanf("%d%d", &h[i], &w[i]);
int l = 1, r = 1e5;
while (l < r)
{
int mid = r + l + 1 >> 1;
if (check(mid))l = mid;
else r = mid - 1;
}
cout << l << endl;
return 0;
}