n = int(input())
if n == 1:
  print(2)
  exit()
if n == 2:
	print(3)
	exit()
ans = n - 1
for k in range(1, n+10):
  if k ** 2 > n:
    break
  if n % k:
  	continue
  for j in range(1, n):
  	p = (n - k) // j
  	if p <= k or j ** 2 > n:
  		break
  	if (n - k) % j:
  		continue
  	tmp = n
  	flg = 1
  	while tmp:
  		if tmp % p != k:
  			flg = 0
  			break
  		tmp //= p
  	if flg:
  		ans = min(ans, p)
  	p = j
  	tmp = n
  	flg = 1
  	while tmp:
  		if tmp % p != k:
  			flg = 0
  			break
  		tmp //= p
  	if flg:
  		ans = min(ans, p)
print(ans)