#include <bits/stdc++.h>
#define int long long 
using namespace std;


signed main() {
  int N;
  cin >> N;
  
  int ans = 0;
  for( int i = 1; i <= sqrt(N); i++ ){
    if( N % i == 0 && N/i != i ){
      ans += i;
      ans += N/i;
    }
  }
  cout << ans << endl;
    
}