//uva11401 #include<iostream> using namespace std; const int N = 1000000 + 10; long long a[N]; int main() { a[3] = 0; for(long long i = 4; i < N; i++) { a[i] = a[i - 1] + ((i - 1) * (i - 2) / 2 - (i - 1 - i / 2)) / 2; } int n; while(cin >> n) { if(n < 3) break; cout << a[n] << endl; } return 0; }