from sys import stdin

def main():
    input = lambda: stdin.readline()[:-1]
    N = int(input())

    n = int(N ** 0.5)
    a = set()
    for i in range(1, n + 1):
        div_, mod_ = divmod(N, i)
        if not mod_:
            a.add(i)
            a.add(div_)
    print(sum(a))

main()