1 #include <iostream> 2 #include <cmath> 3 using namespace std; 4  5 int main() { 6     int n; 7     while (cin >> n && n) { 8         long long ans = 0, last = 0; 9         for (int i = 0, a; i < n; i++) {10             cin >> a;11             ans += abs(last);12             last += a;13         }14         cout << ans << endl;15     }16     return 0;17 }