import sequtils,algorithm,math
proc getchar_unlocked():char {. importc:"getchar_unlocked",header: "<stdio.h>" .}
proc scan(): int =
  var minus = false
  while true:
    var k = getchar_unlocked()
    if k == '-' : minus = true
    elif k < '0' or k > '9': break
    else: result = 10 * result + k.ord - '0'.ord
  if minus: result *= -1

let n = scan()
var Y = newSeqWith(n,scan())
Y.sort(cmp)
let mid = Y[n div 2]
echo Y.foldl(a+abs(b-mid),0)