def add(a, b):
    return a + b

def subtract(a, b):
    return a - b

def multiply(a, b):
    return a * b

def divide(a, b):
    if b == 0:
        return "Error: Cannot divide by zero"
    return a / b
while True:
# Main program
    print("\n=== Simple Calculator ===")
    print("Select operation:")
    print("1. Add")
    print("2. Subtract")
    print("3. Multiply")
    print("4. Divide")

    choice = input("Enter choice (1/2/3/4): ")

    num1 = float(input("Enter first number: "))
    num2 = float(input("Enter second number: "))

    if choice == "1":
        print("Result:", add(num1, num2))
    elif choice == "2":
        print("Result:", subtract(num1, num2))
    elif choice == "3":
        print("Result:", multiply(num1, num2))
    elif choice == "4":
        print("Result:", divide(num1, num2))
    else:
        print("Invalid choice")
        