#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;

typedef long long LL;
const int N = 1e5 + 5;
int n, k;
int h[N], w[N];

//判断x长度是否可行
bool check(int x){
    LL sum = 0;
    for(int i = 0; i < n; i++){
        sum += (LL)(h[i] / x) * (w[i] / x);
    }
    if(sum >= k) return true;
    else return false;
}

int main(){
    scanf("%d%d", &n, &k);
    for(int i = 0; i < n; i++) scanf("%d%d", &h[i], &w[i]);
    int l = 1, r = 1e5;
    while(l < r){
        int mid = l + r + 1 >> 1;
        if(check(mid)){
            l = mid;
        }else{
            r = mid - 1;
        }
    }
    cout << l << endl;
    return 0;
}