import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n = sc.nextInt();
        
        Integer[] a = new Integer[n];
        
        for(int i = 0; i < n; i++) a[i] = sc.nextInt();
        
        int alice = 0;
        int bob = 0;
        
        Arrays.sort(a, Collections.reverseOrder());
        
        for(int i = 0; i < n; i++){
            if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            }
        }
        
        System.out.println(Math.abs(alice-bob));
    }
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n = sc.nextInt();
        
        Integer[] a = new Integer[n];
        
        for(int i = 0; i < n; i++) a[i] = sc.nextInt();
        
        int alice = 0;
        int bob = 0;
        
        Arrays.sort(a, Collections.reverseOrder());
        
        for(int i = 0; i < n; i++){
            if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            }
        }
        
        System.out.println(Math.abs(alice-bob));
    }
} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n = sc.nextInt();
        
        Integer[] a = new Integer[n];
        
        for(int i = 0; i < n; i++) a[i] = sc.nextInt();
        
        int alice = 0;
        int bob = 0;
        
        Arrays.sort(a, Collections.reverseOrder());
        
        for(int i = 0; i < n; i++){
            if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            }
        }
        
        System.out.println(Math.abs(alice-bob));
    } main {
        Scanner sc = new Scanner(System.in);
        
        int n = sc.nextInt();
        
        Integer[] a = new Integer[n];
        
        for(int i = 0; i < n; i++) a[i] = sc.nextInt();
        
        int alice = 0;
        int bob = 0;
        
        Arrays.sort(a, Collections.reverseOrder());
        
        for(int i = 0; i < n; i++){
            if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            }
        }
        
        System.out.println(Math.abs(alice-bob));
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc Integer[] a = new Integer[n]; a new Integer[n] n for(int i = 0; i < n; i++) a[i] = sc.nextInt(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i a[i] = sc.nextInt(); a[i] = sc.nextInt() a[i] a i sc.nextInt() sc.nextInt sc int alice = 0; alice 0 int bob = 0; bob 0 Arrays.sort(a, Collections.reverseOrder()) Arrays.sort Arrays a Collections.reverseOrder() Collections.reverseOrder Collections for(int i = 0; i < n; i++){
            if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            }
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            }
        } {
            if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            }
        } if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            } i % 2 == 0 i % 2 i 2 0 {
                alice+=a[i];
            } alice+=a[i] alice a[i] a i {
                bob+=a[i];
            } bob+=a[i] bob a[i] a i System.out.println(Math.abs(alice-bob)) System.out.println System.out System System.out Math.abs(alice-bob) Math.abs Math alice-bob alice bob String[] args args public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n = sc.nextInt();
        
        Integer[] a = new Integer[n];
        
        for(int i = 0; i < n; i++) a[i] = sc.nextInt();
        
        int alice = 0;
        int bob = 0;
        
        Arrays.sort(a, Collections.reverseOrder());
        
        for(int i = 0; i < n; i++){
            if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            }
        }
        
        System.out.println(Math.abs(alice-bob));
    }
} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n = sc.nextInt();
        
        Integer[] a = new Integer[n];
        
        for(int i = 0; i < n; i++) a[i] = sc.nextInt();
        
        int alice = 0;
        int bob = 0;
        
        Arrays.sort(a, Collections.reverseOrder());
        
        for(int i = 0; i < n; i++){
            if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            }
        }
        
        System.out.println(Math.abs(alice-bob));
    }
} Main
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n = sc.nextInt();
        
        Integer[] a = new Integer[n];
        
        for(int i = 0; i < n; i++) a[i] = sc.nextInt();
        
        int alice = 0;
        int bob = 0;
        
        Arrays.sort(a, Collections.reverseOrder());
        
        for(int i = 0; i < n; i++){
            if(i % 2 == 0){
                alice+=a[i];
            }else{
                bob+=a[i];
            }
        }
        
        System.out.println(Math.abs(alice-bob));
    }
}
