1 #include <bits/stdc++.h>
 2 using namespace std;
 3 
 4 int t;
 5 long long n;
 6 
 7 int main()
 8 {
 9     scanf("%d",&t);
10     while(t--) {
11         scanf("%d",&n);
12         if(n%3 == 0) {
13             printf("%lld\n",n/3*n/3*n/3);
14         } else if(n%4 == 0) {
15             printf("%lld\n",n/2*n/4*n/4);
16         } else {
17             printf("-1\n");
18         }
19     }
20     
21     return 0;
22 }