"""
Térinformatikai algoritmusok
Python alapismeretek
Máté Cserép <mcserep@inf.elte.hu>
"""

import math

n = int(input("Give N:"))
print("N is " + str(n))

if n < 1:
	print("N must be positive")
elif n == 1:
  print("1 is NOT a prime number")
else:
  is_prime = True
  i = 2
  while i < math.sqrt(n) and is_prime:
    print("Testing " + str(i))
    if n % i == 0:
      is_prime = False
    i += 1	

#  for i in range(2, n):
#    print("Testing " + str(i))
#    if n % i == 0:
#      is_prime = False
#      break
      
  if is_prime:
    print(str(n) + " is a prime number")
  else:
    print(str(n) + " is NOT a prime number")