//uva1730 #include <stdio.h> using namespace std; int main() { long long n; while (scanf("%lld", &n) == 1 && n) { long long l = 1, r, val; long long ret = 0; while (l <= n) { val = n / l; r = n / val; ret += val * ((l + r) * (r - l + 1) / 2); l = r + 1; } printf("%lld\n", ret - 1); } return 0; }