from math import sqrt, floor


def calc_positive_divisors(num: int) -> list[int]:
    small_divisors = []
    large_divisors = []
    for n in range(1, floor(sqrt(num))+1):
        if num % n == 0:
            small_divisors.append(n)
            large_divisors.append(num//n)
    if small_divisors[-1] == large_divisors[-1]:
        large_divisors.pop()
    divisors = small_divisors + list(reversed(large_divisors))
    return divisors


def main():
    N = int(input())
    print(sum(calc_positive_divisors(N)))


if __name__ == "__main__":
    main()