from sys import exit
from math import sqrt

def check(n, p):
	res = set()
	while n:
		res.add(n % p)
		n //= p
	return len(res) == 1

n = int(input())
p = 2
while p * p <= n:
	if check(n, p):
		print(p)
		exit()
	p += 1

for i in range(int(sqrt(n)), 0, -1):
	if n % i != 0:
		continue
	if i < n // i - 1:
		print(n // i - 1)
		exit()

print(n + 1)