#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<ll,ll>;
#define rep(i,n) for(int (i) = 0; i<(n); i++)

const int N = 100000;
const ll inf = 1e18;

ll gcd(ll a,ll b){
	if(a%b==0) return b;
	return gcd(b,a%b);
}

int main(){
    int n; ll k;
    cin >> n >> k;
    vector<ll> a(n), b(n);
    rep(i,n) cin >> a[i];
    rep(i,n) cin >> b[i];

    // 二分探索
    int ok = 1, ng = *min_element(a.begin(),a.end())+1;
    while(1<abs(ok-ng)){
        int mid = (ok+ng)/2;
        ll sum = 0; // 加算が必要な回数
        rep(i,n){
            int c = 0;
            while(gcd(a[i],b[i]+c)<mid) c++;
            sum += c;
        }
        if(sum<=k) ok = mid;
        else ng = mid;
    }

    cout << ok << endl;

}