class Yukicoder
  def initialize
    remain = gets.to_i
    n = gets.to_i
    candy = []

    n.times do
      candy << gets.to_i
    end

    answer = 0

    if candy.size == 1
      puts "0"
      return
    end

    a = 0
    b = candy.max
    answer = candy.inject(:+)

    while a < b-2
      c = a + (b-a)/3
      d = [a + 2 * ((b-a)/3), b].min

      v1 = candy.inject(0){|sum,i| sum += (c < i)? i-c : c-i}
      v2 = candy.inject(0){|sum,i| sum += (d < i)? i-d : d-i}

      if v1 < v2
        b = d
      else
        a = c+1
      end
    end

    min_val = Float::INFINITY

    (a-100).upto(b+100) do |i|
      up_val = 0
      down_val = 0

      candy.each do |c|
        if c < i
          up_val += i-c
        else
          down_val += c-i
        end
      end

      if up_val <= remain + down_val
        min_val = [min_val, down_val + up_val].min
      end
    end
    puts min_val
  end
end

Yukicoder.new