output_description: Print the maximum possible number of squares lighted by the lamp.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      H W
      S_1
      :
      S_H
attempt: h, w = map(int, input().split())
  mp = []
  h_wall = []
  for i in range(h):
      h_wall_l = []
      l = input()
      mp.append(l)
      for a in range(len(l)):
          if l[a] == "#":
              h_wall_l.append(a)
      h_wall.append(h_wall_l)
  v_wall = []
  for i in range(w):
      vl = ""
      for j in range(h):
          vl += mp[j][i]
      v_wall_vl = []
      for a in range(len(vl)):
          if vl[a] == "#":
              v_wall_vl.append(a)
      v_wall.append(v_wall_vl)
  # h_mp=[]
  # for i in h_wall:
  #     if len(i)!=0:
  #         hll=[]
  #         first=i[0]
  #         for j in range(first):
  #             hll.append(first)
  #         hll.append(-1)
  #         if len(i)>=2:
  #             for j in range(len(i)-1):
  #                 mid=i[j+1]-i[j]-1
  #                 for z in range(mid):
  #                     hll.append(mid)
  #                 hll.append(-1)
  #         if len(hll)<w:
  #             diff = w-len(hll)
  #             for z in range(diff):
  #                 hll.append(diff)
  #     else:
  #         hll=[w for zz in range(w)]
  #     h_mp.append(hll)
  # v_mp = []
  # for i in v_wall:
  #     if len(i)!=0:
  #         vll=[]
  #         first=i[0]
  #         for j in range(first):
  #             vll.append(first)
  #         vll.append(-1)
  #         if len(i)>=2:
  #             for j in range(len(i)-1):
  #                 mid=i[j+1]-i[j]-1
  #                 for z in range(mid):
  #                     vll.append(mid)
  #                 vll.append(-1)
  #         if len(vll)<h:
  #             diff = h-len(vll)
  #             for z in range(diff):
  #                 vll.append(diff)
  #     else:
  #         vll=[h for zz in range(h)]
  #     v_mp.append(vll)
  # # for i in v_mp:
  # #     print(i)
  # # print("---")
  
  # v_mp = [list(x) for x in zip(*v_mp)]
  # # for i in h_mp:
  # #     print(i)
  # # print("---")
  # # for i in v_mp:
  # #     print(i)
  
  # maxx=0
  
  # for i in range(h):
  #     for j in range(w):
  #         hhh = h_mp[i][j]
  #         vvv = v_mp[i][j]
  #         if hhh != -1 and vvv != -1:
  #             temp = hhh+vvv-1
  #             if temp >= maxx:
  #                 maxx=temp
  # print(maxx)
  
problem_description: Statement
  
  There is a grid with H horizontal rows and W vertical columns, and there are
  obstacles on some of the squares.
  
  Snuke is going to choose one of the squares not occupied by an obstacle and
  place a lamp on it. The lamp placed on the square will emit straight beams of
  light in four cardinal directions: up, down, left, and right. In each
  direction, the beam will continue traveling until it hits a square occupied by
  an obstacle or it hits the border of the grid. It will light all the squares
  on the way, including the square on which the lamp is placed, but not the
  square occupied by an obstacle.
  
  Snuke wants to maximize the number of squares lighted by the lamp.
  
  You are given H strings S_i (1 \leq i \leq H), each of length W. If the j-th
  character (1 \leq j \leq W) of S_i is `#`, there is an obstacle on the square
  at the i-th row from the top and the j-th column from the left; if that
  character is `.`, there is no obstacle on that square.
  
  Find the maximum possible number of squares lighted by the lamp.
samples: [{"input": "4 6\n    #..#..\n    .....#\n    ....#.\n    #.#...", "output": "8\n    \n\nIf Snuke places the lamp on the square at the second row from the top and the\nsecond column from the left, it will light the following squares: the first\nthrough fifth squares from the left in the second row, and the first through\nfourth squares from the top in the second column, for a total of eight\nsquares.\n\n* * *"}, {"input": "8 8\n    ..#...#.\n    ....#...\n    ##......\n    ..###..#\n    ...#..#.\n    ##....#.\n    #...#...\n    ###.#..#", "output": "13"}]