ior = io.read
local h, w = ior("*n", "*n", "*l")
local xs, ys, cnt = {}, {}, 0
local str =""
for i_h = 1, h do
  str = ior()
  for i_w = 1, w do
    if(str:sub(i_w, i_w) == "1") then
      table.insert(xs, i_w)
      table.insert(ys, i_h)
      cnt = cnt + 1
    end
  end
end
local msq, mmi = math.sqrt, math.min
local function getlen(x, y)
  local len = 0
  for i = 1, cnt do
    len = len + msq((x - xs[i]) * (x - xs[i]) + (y - ys[i]) * (y - ys[i]))
  end
  return len
end
local minlen = getlen(1, 0)
for i_w = 2, w do
  minlen = mmi(minlen, getlen(i_w, 0))
end
for i_w = 1, w do
  minlen = mmi(minlen, getlen(i_w, h + 1))
end
for i_h = 1, h do
  minlen = mmi(minlen, getlen(0, i_h))
end
for i_h = 1, h do
  minlen = mmi(minlen, getlen(w + 1, i_h))
end
print(string.format("%.8f", minlen))