#include <bits/stdc++.h>

using namespace std;
const int N = 1e5+10;

int n,k;
int h[N],w[N];

int check_i(int x,int i){//对每一块巧克力检查，能分出来多少块
    int a = h[i]/x;
    int b = w[i]/x;
    return a*b;
}

bool check(int x)//检查巧克力够不够分
{   
    int sum = 0;
    for(int i = 1; i<=n;i++){
        sum+=check_i(x,i);        
    }
    if(sum>=k)return true;
    return false;
}

int main(){
    cin>>n>>k;
    for(int i = 1;i<=n;i++)cin>>h[i]>>w[i];
    int l = 0;
    int 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;
}