#include<bits/stdc++.h>
using namespace std;
using ll=long long;

#include<atcoder/modint>
using namespace atcoder;
using mint=modint1000000007;

void solve(){
    ll N,K,r=1,an=1e18;
    cin>>N>>K;
    vector<ll> A(N);
    for(int i=0;i<N;i++)cin>>A[i],r*=A[i];
    for(int i=0;i<N;i++)an=min(an,r*(A[i]-K)/A[i]);
    cout<<an<<"\n";
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int T=1;
    cin>>T;
    while(T--)solve();
}