----------/分巧克力/----------

#include <bits/stdc++.h>

using namespace std;

const int N = 100010;

pair<int, int> num[N];

int n, k;

    //-----*/简化循环写法/*-----//

#define f(i,n) for (int i = 0; i < n; i++)

    //-----*/判断/*-----//

bool ck(int mid)
{
int ans = 0;
f(i,n)
ans += (num[i].first / mid) * (num[i].second / mid);
return ans >= k;
}

int main()
{
scanf("%d%d", &n, &k);
f(i,n)
scanf("%d%d", &num[i].first, &num[i].second);
`

    //-----*/二分查找模板*/-----//

int l = 1, r = N;

while (l < r)
{
int mid = (l + r + 1) >> 1;
if ( ck(mid) ) l = mid;
else r = mid-1;
}

    //-----*/输出r或l都可以*/-----//

printf("%d", l);
return 0;
}
`