#pragma GCC optimize("O3")
#pragma GCC target("avx")
#include <stdio.h>
// #include <vector>
#include <bits/stdc++.h>

using namespace std;
#define int long long
#define REP(i, n) for (int i = 0; i < (n); i++)
int scan() {
  auto minus = false;
  int 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 Y[1000010];
signed main() {
  int n = scan();
  REP(i, n) Y[i] = scan();
  // sort(Y, Y + n);
  nth_element(Y, Y + n / 2, Y + n);  // n/2までソートで足りる
  int mid = Y[n / 2];
  int ans = 0;
  REP(i, n) ans += abs(Y[i] - mid);
  printf("%lld\n", ans);
}