def helper(n: i64, a: i64, b: i64) -> i64:
    if n < 1:
        return a + b

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

@exported
def fib(n: i64) -> i64:
    if n == 0:
        return 0

    if n == 1:
        return 1

    return helper(n - 1, 0, 1)

@exported
def testEntry() -> i64:
    return fib(40)