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

int main(){
    long long n;
    cin >> n;
    long long s = 0;
    for (long long i = 1; i * i <= n; ++i){
        if (n % i == 0){
            s += i;
            s += n/i;
            if (i * i == n) s -= i;
        }
    }
    cout << s << endl;
    return 0;
}