#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

int main() {
  ll N;
  scanf("%lld", &N);

  ll ans = 0;
  for (ll i = 1; i * i <= N; ++i) {
    if (N % i == 0) {
      ans += i;
      if (N / i != i) ans += N / i;
    }
  }
  printf("%lld\n", ans);
  return 0;
}