n = int(input())

def divisors(n):
    div = []
    i = 1
    while(i * i <= n):
        if n % i == 0:
            div.append(i)
            if i * i != n:
                div.append(n // i)
        i += 1
    return div

div = sorted(divisors(n))

if div[1] == 2:
    print(div[2])
else:
    print(div[1])