def min(a,b); a < b ? a : b; end
  
H,W = gets.split.map(&:to_i)
P = H.times.map{ gets.chomp }

def cost(x0, y0)
  s = 0.0

  (1 .. W).each do |x|
    (1 .. H).each do |y|
      x2 = (x - x0).abs ** 2
      y2 = (y - y0).abs ** 2
      s += Math.sqrt(x2 + y2) if P[y-1][x-1] == '1'
    end
  end

  return s
end

cost_min = Float::INFINITY

[0, W + 1].each do |x0|
  (1 .. H).each do |y0|
    cost_min = min(cost_min, cost(x0, y0))
  end
end

[0, H + 1].each do |y0|
  (1 .. W).each do |x0|
    cost_min = min(cost_min, cost(x0, y0))
  end
end

puts "%.8f" % cost_min