def prime_factorize(n):
    a = []
    while n % 2 == 0:
        a.append(2)
        n //= 2
    f = 3
    while f * f <= n:
        if n % f == 0:
            a.append(f)
            n //= f
        else:
            f += 2
    if n != 1:
        a.append(n)
    return a

a = int(input())

b = prime_factorize(a)

c = 10**10
d = 10**10
for i in range(len(b)):
    if i % 2 == 0:
        c *= b[i]
    else:
        d *= b[i]

print(c + d - 2)
