import streamlit as st

def main():
    st.title("Simple Calculator")
    st.write("A basic calculator built with Streamlit.")

    # Input fields for numbers
    num1 = st.number_input("Enter the first number:", step=1.0)
    num2 = st.number_input("Enter the second number:", step=1.0)

    # Dropdown for selecting operation
    operation = st.selectbox(
        "Choose an operation:",
        ("Addition", "Subtraction", "Multiplication", "Division")
    )

    # Perform calculation based on selected operation
    result = None
    if st.button("Calculate"):
        if operation == "Addition":
            result = num1 + num2
        elif operation == "Subtraction":
            result = num1 - num2
        elif operation == "Multiplication":
            result = num1 * num2
        elif operation == "Division":
            if num2 != 0:
                result = num1 / num2
            else:
                st.error("Division by zero is not allowed.")
        if result is not None:
            st.success(f"The result is: {result}")

if __name__ == "__main__":
    main()