local mab = math.abs
local mmi, mma = math.min, math.max
local n = io.read("*n")
local t = {}
for i = 1, n do t[i] = io.read("*n") end
table.sort(t)
local dp = {}
for i = 1, n do
  dp[i] = 2 * 1000000007
end
dp[2] = t[2] - t[1]
if 2 < n then
  dp[3] = t[3] - t[1]
end
for i = 2, n - 2 do
  dp[i + 2] = mmi(dp[i + 2], dp[i] + t[i + 2] - t[i + 1])
  if i ~= n - 2 then
    dp[i + 3] = mmi(dp[i + 3], dp[i] + t[i + 3] - t[i + 1])
  end
end
print(dp[n])