Time Limit: 2 sec / Memory Limit: 1024 MB
Score : 200200 points
Problem Statement
N people numbered 1,2,…,�1,2,…,N were in �M photos. In each of the photos, they stood in a single line. In the �i-th photo, the �j-th person from the left is person ��,�ai,j.
Two people who did not stand next to each other in any of the photos may be in a bad mood.
How many pairs of people may be in a bad mood? Here, we do not distinguish a pair of person �x and person �y, and a pair of person �y and person �x.
Constraints
- 2≤�≤502≤N≤50
- 1≤�≤501≤M≤50
- 1≤��,�≤�1≤ai,j≤N
- ��,1,…,��,�ai,1,…,ai,N contain each of 1,…,�1,…,N exactly once.
- All values in the input are integers.
Input
The input is given from Standard Input in the following format:
�N �M �1,1a1,1 …… �1,�a1,N ⋮⋮ ��,1aM,1 …… ��,�aM,N
Output
Print the answer.