def pt_in(pt, poly):
    testX, testY = pt
    last = poly[-1]
    answer = False
    for now in poly:
        nowX, nowY = now
        lastX, lastY = last
        if (nowY > testY) != (lastY > testY) and (testX < (lastX - nowX) * (testY - nowY)/(lastY - nowY) + nowX):
            answer = not answer
        last = now
    return answer