#include <stdio.h>
#include <bits/stdc++.h>
using namespace std;
#define REP(i, n) for (int i = 0; i < (n); i++)
int scan() {
  auto minus = false;
  auto result = 0;
  while (true) {
    auto k = getchar_unlocked();
    if (k == '-')
      minus = true;
    else if (k < '0' || k > '9')
      break;
    else
      result = 10 * result + k - '0';
  }
  return result * (minus ? -1 : 1);
}
int main() {
  auto n = scan();
  vector<int> Y(n);
  REP(i, n) Y[i] = scan();
  sort(Y.begin(), Y.end());
  auto mid = Y[n / 2];
  auto ans = 0;
  REP(i, n) ans += abs(Y[i] - mid);
  printf("%d\n", ans);
}