Fibonacci index

def main():
    index = eval(input("Enter an index for a fibonacci number: "))

    print("The Fibonacci number at index", index, "is", fib(index))

def  fib(index):
    if index == 0:  # Base case
        return 0
    elif index == 1:   # Base case
        return 1
    else:   # Reduction and recursive calls
        return fib(index - 1) + fib(index - 2)


main()  # Call the main function