from sys import argv

def binomcoeff(n,k):
    nom = 1
    denum = 1
    for i in range(n-k):
        nom *= (n-i)
        denum *= (i+1)
    v = nom//denum
    return v

def is_prime(n):
    if n <= 1:
        return False
    for k in range(1,n):
        bc = binomcoeff(n,k)
        r = bc % n
#        print("%d %% %d = %d" % (bc,n,r))
        if r != 0:
            return False
    return True

if len(argv) > 1:
    p = int(argv[1])
    if is_prime(p):
        print("%d is a prime" % p)
    else:
        print("%d is not a prime" % p)
else:
    print("%s <number>" % argv[0])