N = gets.to_i
Y = gets.split.map(&:to_i).sort
dp = Array.new(N, Float::INFINITY)
dp[1] = Y[1] - Y[0]
dp[2] = Y[2] - Y[0]

3.upto(N - 1) do |i|
  y = Y[i]

  2.upto(3) do |k|
    v = dp[i - k] + y - Y[i - k + 1]
    dp[i] = v if dp[i] > v
  end
end

puts dp[N - 1]