from math import floor, sqrt


def main():
    N = int(input())
    money = 0
    numbers = [2]
    numbers.extend(range(3, floor(sqrt(N))+1, 2))
    for number in numbers:
        while N > 1 and N % number == 0:
            money += number
            N //= number
        if N == 1:
            break
    else:
        money += N

    print(money)


if __name__ == "__main__":
    main()