def get_divisors(n):
    # 約数列挙
    divisors = set()
    for i in range(1, int(n**0.5) + 1):
        if n % i == 0:
            divisors.add(i)
            divisors.add(n // i)
    return list(divisors)

N = int(input())
for p in get_divisors(N):
    if p > 2:
        print(p)
        exit()