Use A$-$star search method and find the optimal path from staring location L to destination location B$.$ It is necessary to show all the necessary cost computations and illustrate the expanded tree. The distance function must be decided by yourself so that you can check the lecture notes that the distance function is suitable for this type of problem. Show all calculations within the MS Document step by step. Handwritten images are not accepted in the MS doc file. Show clear calculations and clear expanation i don't want chat gpt generated answer.