Given the number of arrays (e.g., 4) and number of items (e.g., 5) in the arrays ( note that the number of items are the same for all arrays), find out how many pairs have the same order across all the arrays.

Sample Input: input.txt

4 5
4 1 2 3 5
4 1 3 5 2
4 2 1 3 5
3 4 1 2 5

Sample Output : output.txt

5

For the above sample data, number of pairs matching requirements are 5: [4, 1], [4, 2], [4, 5], [1, 5], [3, 5]

USACO 编程竞赛概要: 铜级题 #1

给定数组数量(例如：4)和数组内数值长度(例如：5)，找出在所有数组里面顺序都保持一致的组合数。

输入样例：input.txt

4 5
4 1 2 3 5
4 1 3 5 2
4 2 1 3 5
3 4 1 2 5

输出样例：output.txt

5

譬如上面符合要求的组合数为 5：[4, 1], [4, 2], [4, 5], [1, 5], [3, 5]。

Python Solution: