#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <iomanip>
#include <cmath>
#include <stdio.h>
#include <queue>
#include <deque>
#include <cstdio>
#include <set>
#include <map>
#include <bitset>
#include <stack>
#include <cctype>
#include <boost/multiprecision/cpp_dec_float.hpp>
#include <boost/multiprecision/cpp_int.hpp>
namespace mp = boost::multiprecision;
using Bint = mp::cpp_int;
using namespace std;
int main() {
	Bint n;
	cin >> n;
	Bint ans = 0;
	for (Bint i = 1; i * i <= n; i++) {
		if (n % i == 0) {
			if (n*(n - 1)/2 % i == 0) {
				ans += i;
			}
			if (n*(n - 1)/2 % (n / i) == 0 && i != n / i) {
				ans += n / i;
			}
		}
	}
	cout << ans << endl;
}