#include <bits/stdc++.h>

using namespace std;
typedef long long ll;

// #define DEBUG

int main()
{

#ifdef DEBUG
    cout << "DEBUG MODE" << endl;
    ifstream in("input.txt"); //for debug
    cin.rdbuf(in.rdbuf());    //for debug
#endif

    ll n, s;
    cin >> n;
    s = 0;
    for (int i = 1; i < sqrt(n+1); i++){
        if (n % i == 0){
            s += i;
            if (i != n / i)
                s += n / i;
        }
    }
    cout << s << endl;

    return 0;
}