#!/usr/bin/env python3


import math


EPS = 0.0001


def divisors(n):
    ds = []
    for i in range(1, math.floor(math.sqrt(n) + EPS) + 1):
        d, m = divmod(n, i)
        if m == 0:
            ds.append(i)
            if i != d:
                ds.append(d)
    ds.sort()
    return ds


def sum_of_divisors(n):
    return sum(divisors(n))


def main():
    n = int(input())
    print(sum_of_divisors(n))


if __name__ == "__main__":
    main()