n = int(input())
n_c = n

primes = []
while n % 2 == 0:
    primes.append(2)
    n //= 2

f = 3
while f * f <= n_c:
    while n % f == 0:
        primes.append(f)
        n //= f
    f += 2

if n != 1:
    primes.append(n)

print(sum(primes))