local n = io.read("*n")
local a = {}
for i = 1, n do
  a[i] = io.read("*n")
end
table.sort(a)
local hn = math.floor(n / 2)
local y = 0
for i = 1, hn do
  y = y + a[i]
end
y = -y
local x = 0
for i = hn + 1, n do
  x = x + a[i]
end
local ans = x - y
ans = tostring(1LL * ans):gsub("LL", "")
print(ans)