num = int(input("Enter a number: "))
if num > 1:
    for i in range(2, num):
        if (num - i * (num // i)) == 0:  # Checking if there's no remainder using multiplication
            print(f"{num} is not a prime number.")
            break
    else:
        print(f"{num} is a prime number.")
else:
    print(f"{num} is not a prime number.")