contavalori

def conta(a,valmin,valmax):
    return contavalori(a,valmin,valmax,0)


def contavalori(a,valmin,valmax,liv):
    conta = 0

    if a.val % 2 == 0 and liv % 2 != 0 and a.val < valmin and a.val > valmax:
        conta += 1


    if a.sx == None and a.dx == None:
        return conta


    if a.sx != None:
        conta += contavalori(a.sx,valmin,valmax, liv+1)

    if a.dx != None:
        conta += contavalori(a.dx,valmin,valmax, liv+1)

    return conta