N = int(input())
def divisor(n):
  cd = []
  i = 1
  while i*i <= n:
    if n%i==0:
      # cd.append(i)
      if n//i - i >= 2:
        cd.append(n//i)
    i += 1
  return cd[-1]

if N<=2:
  print(2)
  exit()
ans = divisor(N)-1
for m in range(3,41):
  p = 2
  while pow(p,m)-1<=N*(p-1):
    if (N*(p-1))%(pow(p,m)-1)==0:
      ans = min(ans, p)
      break
    p += 1
print(ans)