search for: tpair

Hi, All, I have an n by m matrix with each entry between 1 and 15000. I want to know the frequency of each pair in 1:15000 that occur together in rows. So for example, if the matrix is 2 5 1 6 1 7 8 2 3 7 6 2 9 8 5 7 Pair (2,6) (un-ordered) occurs together in rows 1 and 3. I want to return the value 2 for this pair as well as that for all pairs. Is there a fast way to do this avoiding loops?