Maximum Number

Harry accidently got selected for triwizard tournament.After successfully completing two tasks he comes accross the third task.In this task there is a maze M × N with single digit positive integers at each cell.The rules for traversal in the maze is such that from a cell (i,j) one can move to upper cell if i+j is power of 2 else can move to upper,upper left and upper right cell.The contestants nee