/* -*- coding: utf-8 -*-
 *
 * 1374.cc:  No.1374 Absolute Game - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

const int MAX_N = 100000;

/* typedef */

typedef long long ll;

/* global variables */

int as[MAX_N];
ll ss[2];

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);
  for (int i = 0; i < n; i++) scanf("%d", as + i);
  sort(as, as + n);

  for (int i = 0; i < n; i++) ss[i & 1] += as[i];
  ll d = abs(ss[0]) - abs(ss[1]);
  if (! (n & 1) && d < 0) d = -d;

  printf("%lld\n", d);
  return 0;
}