n = int(input())

def make_divisors(n):
    divisors = []
    for i in range(1, int(n**0.5)+1):
        if n % i == 0:
            divisors.append(i)
            if i != n // i:
                divisors.append(n//i)

    divisors.sort()
    return divisors

d = make_divisors(n)
for i in d:
    if i == 1 or i == 2:
        continue
    print(i)
    exit()