import sys


def solve():
  input = sys.stdin.read
  data = input().split()
  if not data:
    return

  H = int(data[0])
  W = int(data[1])
  S = data[2:]

  # カギの始点を管理する配列
  # 各マスが横・縦のカギの始点かどうかを調べる
  is_horiz_start = [[False] * W for _ in range(H)]
  is_vert_start = [[False] * W for _ in range(H)]

  horiz_len = {}
  vert_len = {}

  for i in range(H):
    for j in range(W):
      if S[i][j] == ".":
        # 横のカギの始点判定
        is_h = (j == 0 or S[i][j - 1] == "#") and (
            j + 1 < W and S[i][j + 1] == "."
        )
        if is_h:
          is_horiz_start[i][j] = True
          # 長さを計算
          length = 0
          jj = j
          while jj < W and S[i][jj] == ".":
            length += 1
            jj += 1
          horiz_len[(i, j)] = length

        # 縦のカギの始点判定
        is_v = (i == 0 or S[i - 1][j] == "#") and (
            i + 1 < H and S[i + 1][j] == "."
        )
        if is_v:
          is_vert_start[i][j] = True
          # 長さを計算
          length = 0
          ii = i
          while ii < H and S[ii][j] == ".":
            length += 1
            ii += 1
          vert_len[(i, j)] = length

  # 添字の割り当て (上から、同じ行は左から)
  keys = []
  for i in range(H):
    for j in range(W):
      if is_horiz_start[i][j] or is_vert_start[i][j]:
        keys.append((i, j))

  K = len(keys)
  print(K)

  for idx, (i, j) in enumerate(keys):
    r_str = "-"
    c_str = "-"

    if is_horiz_start[i][j]:
      L = horiz_len[(i, j)]
      # 長さ L の適当な文字列を作る (例: 'a' が L 個)
      r_str = "a" * L

    if is_vert_start[i][j]:
      L = vert_len[(i, j)]
      c_str = "a" * L

    print(f"{r_str} {c_str}")


if __name__ == "__main__":
  solve()