import sys

def process_message(message):
    base_message = f"Processed message: {message}"
    extra_chars = 'a' * (4000 - len(base_message))
    return base_message + extra_chars

if __name__ == "__main__":
    if len(sys.argv) > 1:
        user_message = sys.argv[1]
        result = process_message(user_message)
        print(result)
    else:
        print("No message provided")