Using Floyd-Warshall algorithm to count number of paths between 2 vertices

Given an directed unweighted acylic graph, I am trying to adapt Floyd-Warshall algorithm to count the number of paths between 2 vertices. My code currently looks like this:

   for all k in 1 to n
      for all i in 1 to n 
        for all j in 1 to n
             Aij = Aij + ( Aik * Akij).
 

Therefore, instead of checking and replacing for min distance, I am doing the following:

count of paths between (i,j) without k + ( count of paths from i to k * count of paths from k *j )

My final array, should have the number of paths between any 2 vertices.

I am not able to prove that this does not give me the count of simple paths between 2 vertices, but there are no suggestions to use this approach elsewhere.

Can someone provide a counter example where this fails?

PS: This is not my homework, but just a programming exercise I picked up.

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