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

int main(){
    ll N;
    cin >> N;

    ll ans = 0;
    for (ll p = 1; p*p <= N; p++){
        if (N%p == 0) ans += p+N/p;
        if (p*p == N) ans -= p;
    }

    cout << ans << endl;
}