def helper(n: i32, a: i32, b: i32) -> i32:
    if n < 1:
        return a + b

    return helper(n - 1, a + b, a)

def fib(n: i32) -> i32:
    if n == 0:
        return 0

    if n == 1:
        return 1

    return helper(n - 1, 0, 1)

@exported
def testEntry() -> i32:
    return fib(40)