#include<iostream>
using namespace std;
typedef long long LL;
const int N = 100010;
int a[N], b[N];
int n, k;
bool check(int x)
{
    LL res = 0;
    for (int i = 1; i <= n; ++ i)
    {
        int h = a[i] / x, w = b[i] / x;
        res += h * w;
        if (res >= k) return true;
    }
    return false;
}
int main()
{
    cin >> n >> k;
    for (int i = 1; i <= n; ++ i) scanf("%d%d", &a[i], &b[i]);
    int l = 1, r = 1e9;
    while (l < r)
    {
        int mid = l + r + 1 >> 1;
        if (check(mid)) l = mid;
        else r = mid - 1;
    }
    cout << l << endl;
    return 0;
}