def divisor(N):
    ass = []
    for i in range(1, int(N ** 0.5) + 1):
        if N % i == 0:
            ass.append(i)

            if i * i == N:
                continue
            ass.append(N // i)

    return ass

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


if __name__ == "__main__":
    main()