def hailstone_length(n):
    if n == 1:
        return 1
    elif n %2 == 0:
        return 1 + hailstone_length(n/2)
    else:
        return 1 + hailstone_length(3*n + 1)

def hailstone_length_NN(n):
    if n == 1:
        return 1
    elif n %2 == 0:
        return 1 + (yield hailstone_length_NN(n/2))
    else:
        return 1 + (yield hailstone_length_NN(3*n + 1))

def exec_with_non_native_stack(gen):
    generators = [gen]
    result = None
    while generators:
        try:
            generators.append(generators[-1].send(result))
            result = None
        except StopIteration as e:
            generators.pop()
            result = e.value
    return result


x = 9_780_657_630
try:
    print(hailstone_length(x))
except RecursionError:
    print("hailstone_length overflowed")

try:
    print(exec_with_non_native_stack(hailstone_length_NN(x)))
except RecursionError:
    print("hailstone_length_NN overflowed")