print("===========================================================")
print("Prime Number Checker")
print("===========================================================")


# Enter a positive integer
num = input("Prime Number Checker\n----------------------------\nEnter a positive integer: ")

# Validate input to ensure user enters a positive integer
while not num.isdigit() or int(num) < 1:
    num = input("Invalid input. Please enter a positive integer: ")

# Convert input to integer
num = int(num)

# Check if entered number is a prime number or not
if num == 1:
    print(f"{num} is not a prime number.")
else:
    is_prime = True
    for i in range(2, int(num/2)+1):
        if num % i == 0:
            is_prime = False
            break
    
    if is_prime:
        print(f"{num} is a prime number.")
    else:
        print(f"{num} is not a prime number.")