City makes a plan for buildings and parking lots on land. The land can be divided into equal sized tiles. Each tile is either a building or parking lot. The height difference between building/parking lots on two adjacent tiles is no more than one. The locations of parking lots on the land are fixed. Write a function to find what is the highest building can be planned. [Adjacency only includes left, right, up and down. Specifically diagonal is not considered - two tiles share an edge to be considered as adjacent]\n\nExample 1\nInput\n```\n- - -\n- - -\n- - P\n```\nOutput: 4 with following arrangement\n```\n4 3 2\n3 2 1\n2 1 P\n```\n\nExample 2\nInput\n```\n- - P\n- - -\n- - P\n```\nOutput: 3 with following arrangement\n```\n2 1 P\n3 2 1\n2 1 P\n```

City makes a plan for buildings and parking lots on land. The land can be divided into equal sized tiles. Each tile is either a building or parking lot. The hei