import sys
from math import sqrt
input = sys.stdin.readline
N = int(input())

for p in range(2, int(sqrt(N)) + 1):
  x = N
  r = x % p
  while x:
    if x % p != r: break
    x -= r
    x //= p
  else:
    print(p)
    break
else: print(N - 1)