P3298 [SDOI2013] Springs

As a proud member of the Jinan Springs History Research Group, Mingming has collected, for $N$ different years, the flow index of different spring zones. This index is a non-negative integer less than $2^{30}$. In year $i$, the flow indices of the six spring zones are $A_{i,1} \sim A_{i,6}$. Now Mingming wants to know how many pairs of different years $i$ and $j$ ($i < j$) have exactly $K$ spring zones whose flow indices are equal in those two years.

The first line contains two integers $N, K$. The next $N$ lines each contain $6$ integers $A_{i,1} \sim A_{i,6}$.

Output a single integer on one line, representing the answer.

Constraints: $1 \le N \le 10^5$，$0 \le A_{i,j} \le 2^{30}$，且保证 $K$ 在 $[0,1,2,3,4,5,6]$ 中均匀随机选取。 Translated by ChatGPT 5