def calculate(a, b, operation):
    if operation == "+":
        return a + b
    if operation == "-":
        return a - b
    if operation == "*":
        return a * b
    if operation == "/":
        if b == 0:
            raise ValueError("Division by zero is not allowed")
        return a / b
    raise ValueError(f"Unsupported operation: {operation}")


def main():
    print("Simple Python Calculator")
    first = float(input("Enter the first number: "))
    operation = input("Choose operation (+, -, *, /): ").strip()
    second = float(input("Enter the second number: "))

    try:
        result = calculate(first, second, operation)
        print(f"Result: {result}")
    except ValueError as error:
        print(f"Error: {error}")


if __name__ == "__main__":
    main()