#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
const int N = 100010;
int n, k;
int h[N], w[N];
int l, r;
int res = 1e9;
int hest = 0;
bool cheak(int x) {
    int sum = 0; 
    for (int i = 0; i < n; i++) {
    sum+= (h[i] / x)*(w[i]/x);
    }
    if (sum >= k)return true;
    return false;
}
int binary_search(int l, int r) {
    while (l + 1 < r) {
        int mid = (l + r) / 2;
        if (cheak(mid))l = mid;
        else r = mid;
    }
    if (cheak(l))return l;
}
int main() {
    cin >> n >> k;
    for (int i = 0; i < n; i++) {
        cin >> h[i] >> w[i];
        hest = max(hest, h[i]);
        hest = max(hest, w[i]);
    }
    l = 0, r = hest + 1;
    res=min(binary_search(l,r),res);
    cout << res;
    return 0;
}