$N$ people numbered $1,2,\ldots,N$ 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 $a_{i,j}$. 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 $x$.

The input is given from Standard Input in the following format: >$N$ $M$\ >$a_{1,1}$ $\ldots$ $a_{1,N}$\ >$\vdots$\ >$a_{M,1}$ $\ldots$ $a_{M,N}$ #### Constraints - $2 \leq N \leq 50$ - $1 \leq M \leq 50$ - $1 \leq a_{i,j} \leq N$ - $a_{i,1},\ldots,a_{i,N}$ contain each of $1,\ldots,N$ exactly once. - All values in the input are integers.

Print the answer.

***For Sample #1:*** The pair of person $1$ and person $4$, and the pair of person $2$ and person $4$, may be in a bad mood.

AtCoder [ABC303B]