HDU 6298

 1 #include <iostream>
 2 using namespace std;
 3 typedef long long ll;
 4 
 5 int main(){
 6     int T;
 7     scanf("%d",&T);
 8     while(T--){
 9         ll n;
10         ll max = 0;
11         scanf("%lld",&n);
12         if(n%3 == 0){
13             max = n*n*n/27;cout<<max<<endl;
14         }
15         
16         else if(n%4 == 0){
17             max = n*n*n/32;cout<<max<<endl;
18         }
19         
20         else 
21         cout<<"-1"<<endl;
22         
23     } 
24     return 0;
25 }