//uva11054 #include <cstdio> #include <iostream> using namespace std; int main() { int n, i; int a[100005]; long long int ans; while (scanf("%d", &n) && n) { for (i = 0 ; i < n ; i++) scanf("%d",&a[i]); ans = 0; for (i = 0 ; i < n ; i++) { ans += (a[i] >= 0 ? a[i] : -a[i]); a[i + 1] = a[i] + a[i + 1]; } printf("%lld\n", ans); } return 0; }