def is_prime(num):
    # Check if the number is less than 2
    if num < 2:
        return False

    # Check for divisibility from 2 up to the square root of the number
    for i in range(2, int(num ** 0.5) + 1):
        if num % i == 0:
            return False

    return True

# Prompt user to enter a positive integer
while True:
    try:
        user_input = int(input("Enter a positive integer: "))
        if user_input > 0:
            break
        else:
            print("Invalid input! Please enter a positive integer.")
    except ValueError:
        print("Invalid input! Please enter a positive integer.")

# Check if the  number is prime or not prime
if is_prime(user_input):
    print(f"{user_input} is a prime number.")
else:
    print(f"{user_input} is not a prime number.")