#include<bits/stdc++.h>
#define INF 0x3f3f3f3f
using namespace std;
const int N=200005;
void solve(){
    int a,b,c,d;
    cin>>a>>b>>c>>d;
    if(a<=3){puts("0");return;}
    b=min(b,c);int as=0;
    for(int i=1;i<=1000;++i){
        int j=min(b-i,d/i);
        if(j<0)continue;
        as=max(as,(i+2)*(j+2));
    }cout<<as<<"\n";
}
int main(){
    // freopen("1.in","r",stdin);
    int t;cin>>t;
    while(t--)solve();
    return 0;
}