#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>

#define INF 100010;

using namespace std;

const int N = 100010;
int wid[N];
int len[N];
int n, k;

int get_sum(int u)
{
    int sum = 0;
    for(int i = 0 ; i < n ; i ++ )
       sum += (wid[i] / u) * (len[i] / u);
    return sum;
} 

int main()
{
    //读入数据
    scanf("%d%d", &n, &k);
    for(int i = 0; i < n; i++) scanf("%d%d", &wid[i], &len[i]);
    int l = 0, r = N;
    while(l < r)
    {
        int mid = l + r + 1>> 1;
        if(get_sum(mid) >= k) l = mid;
        else r = mid - 1;
    }

    cout << l << endl;

    return 0;
}