#include <bits/stdc++.h>
using namespace std;
#define SORT(a) sort(a.begin(), a.end());
typedef long long ll;
const long mod = 1e9 + 7;

int main(void) {
#ifdef DEBUG
  freopen("input.txt", "r", stdin);
#endif

  ios_base::sync_with_stdio(false);
  cin.tie(NULL);

  long B;
  cin >> B;
  int N;
  cin >> N;
  vector<long> C(N);
  for (int i = 0; i < N; i++)
    cin >> C[i];
  SORT(C);
  long candy, ans;
  candy = C[N/2];
  for (int i = 0; i < N; i++)
    ans += abs(candy - C[i]);
  cout << ans << endl;
  return 0;
}