#include<iostream>
#include<vector>
using namespace std;
const int N = 100010;
pair<int, int> PII[N];
int n;
int f(int a) // 边长为a
{
    int sum = 0;
    for(int i = 0;i < n;i++)
    {
        sum += (PII[i].first / a) * (PII[i].second /a);
    }
    return sum;
}
int main()
{
    int  k;
    cin >> n >> k;
    for(int i = 0;i < n;i++)
    {
        cin >> PII[i].first >> PII[i].second; 
    }
    int l = 1, r = N;
    while(l < r)
    {
        int mid = (l+r+1)/2;
        if(f(mid) >= k) l = mid;
        else r = mid - 1;
    }
    cout <<l << endl;
    return 0;
}