local mmi, mma = math.min, math.max
local h, w = io.read("*n", "*n", "*l")
local s = io.read()
local dp1, dp2 = {}, {}
dp1[1] = 0
for i = 2, w do
  if s:sub(i, i) == "k" then
    dp1[i] = dp1[i - 1] + i - 1
  else
    dp1[i] = dp1[i - 1]
  end
end
for i = 2, h do
  local src = i % 2 == 0 and dp1 or dp2
  local dst = i % 2 == 0 and dp2 or dp1
  s = io.read()
  for j = 1, w do
    local add = 0
    if s:sub(j, j) == "k" then
      add = i + j - 2
    end
    if j == 1 then
      dst[j] = src[j] + add
    else
      dst[j] = mmi(dst[j - 1], src[j]) + add
    end
  end
end
local tbl = h % 2 == 0 and dp2 or dp1
print(tbl[w] + h + w - 2)