What's the shortest path from A to R in the array below, if your moves are to be in the repeated length sequence 3, 2, 1, 3, 2, 1... (such as, say ADJMC...), and no two successive moves are in the same direction or in the reverse direction? Moves may be orthogonal or diagonal. No move may end on a hyphen (-) but may jump over them and the R must be reached on exact count.
ABCD-
EFGH-
--IJK
-LM-N
OP-QR