import sys; input = sys.stdin.buffer.readline
sys.setrecursionlimit(10**7)
from collections import defaultdict
con = 10 ** 9 + 7; INF = float("inf")

def getlist():
	return list(map(int, input().split()))

def divisor(N):
	divisor_list = []
	n = int((N ** 0.5) // 1)
	for i in range(1, n):
		if N % i == 0:
			divisor_list.append(i)
			divisor_list.append(int(N // i))

	if n ** 2 == N:
		divisor_list.append(n)
	else:
		if N % n == 0:
			divisor_list.append(n)
			divisor_list.append(int(N // n))

	return sorted(divisor_list)

#処理内容
def main():
	N = int(input())
	div = divisor(N)
	ans = N
	for i in div:
		if i > 2:
			ans = min(ans, i)

	print(ans)




if __name__ == '__main__':
	main()