#!/usr/bin/python# define three list var.z1 = [1,2,3,4,5,6,7,"1st zhu"]z2 = ["2st zhu"]z3 = ["3st zhu"]counter = 0def HANLTA(n, a, b, c):    global counter    if n==1:        counter = counter +1        c.insert(0,a[0])        del a[0]        return    else:        HANLTA(n-1, a, c, b)        counter = counter +1        c.insert(0,a[0])        del a[0]        HANLTA(n-1,b,a,c)HANLTA(7, z1, z2, z3)print z1print z2print z3print counter