题目:有四个数字:1、2、3、4,能组成多少个互不相同且无重复数字的三位数?各是多少?

# -*- coding: UTF-8 -*-
b=[]
for i in range (1,5):
    for j in range(1,5):
        for k in range(1,5):
            if(i != k) and (j != k ) and (i != j):

                b.append([i,j,k])

                print(i, j, k)
print(b)
print (len(b))