import java.util.*;

//くそコード
class Main{
  public static void main(String[] args){
    try(Scanner sc = new Scanner(System.in)){
      int n = Integer.parseInt(sc.nextLine());
      //int a[] = new int[n];
      Integer a[] = new Integer[n];
      for(int i = 0; i < n; i++){
        a[i] = Integer.parseInt(sc.next());
      }
      int Alice = 0;
      int Bob = 0;
      Arrays.sort(a, Collections.reverseOrder());
      
      for(int i = 0; i < n; i++){
        if((i % 2) == 0){
          Alice = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        }
      }
      System.out.println(Alice - Bob);
    }
  }
}
          
       import java.util.*; util.* java class Main{
  public static void main(String[] args){
    try(Scanner sc = new Scanner(System.in)){
      int n = Integer.parseInt(sc.nextLine());
      //int a[] = new int[n];
      Integer a[] = new Integer[n];
      for(int i = 0; i < n; i++){
        a[i] = Integer.parseInt(sc.next());
      }
      int Alice = 0;
      int Bob = 0;
      Arrays.sort(a, Collections.reverseOrder());
      
      for(int i = 0; i < n; i++){
        if((i % 2) == 0){
          Alice = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        }
      }
      System.out.println(Alice - Bob);
    }
  }
} Main public static void main(String[] args){
    try(Scanner sc = new Scanner(System.in)){
      int n = Integer.parseInt(sc.nextLine());
      //int a[] = new int[n];
      Integer a[] = new Integer[n];
      for(int i = 0; i < n; i++){
        a[i] = Integer.parseInt(sc.next());
      }
      int Alice = 0;
      int Bob = 0;
      Arrays.sort(a, Collections.reverseOrder());
      
      for(int i = 0; i < n; i++){
        if((i % 2) == 0){
          Alice = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        }
      }
      System.out.println(Alice - Bob);
    }
  } main {
    try(Scanner sc = new Scanner(System.in)){
      int n = Integer.parseInt(sc.nextLine());
      //int a[] = new int[n];
      Integer a[] = new Integer[n];
      for(int i = 0; i < n; i++){
        a[i] = Integer.parseInt(sc.next());
      }
      int Alice = 0;
      int Bob = 0;
      Arrays.sort(a, Collections.reverseOrder());
      
      for(int i = 0; i < n; i++){
        if((i % 2) == 0){
          Alice = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        }
      }
      System.out.println(Alice - Bob);
    }
  } try(Scanner sc = new Scanner(System.in)){
      int n = Integer.parseInt(sc.nextLine());
      //int a[] = new int[n];
      Integer a[] = new Integer[n];
      for(int i = 0; i < n; i++){
        a[i] = Integer.parseInt(sc.next());
      }
      int Alice = 0;
      int Bob = 0;
      Arrays.sort(a, Collections.reverseOrder());
      
      for(int i = 0; i < n; i++){
        if((i % 2) == 0){
          Alice = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        }
      }
      System.out.println(Alice - Bob);
    } {
      int n = Integer.parseInt(sc.nextLine());
      //int a[] = new int[n];
      Integer a[] = new Integer[n];
      for(int i = 0; i < n; i++){
        a[i] = Integer.parseInt(sc.next());
      }
      int Alice = 0;
      int Bob = 0;
      Arrays.sort(a, Collections.reverseOrder());
      
      for(int i = 0; i < n; i++){
        if((i % 2) == 0){
          Alice = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        }
      }
      System.out.println(Alice - Bob);
    } Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) int n = Integer.parseInt(sc.nextLine()); n Integer.parseInt(sc.nextLine()) Integer.parseInt Integer sc.nextLine() sc.nextLine sc Integer a[] = new Integer[n]; a new Integer[n] n for(int i = 0; i < n; i++){
        a[i] = Integer.parseInt(sc.next());
      } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
        a[i] = Integer.parseInt(sc.next());
      } {
        a[i] = Integer.parseInt(sc.next());
      } a[i] = Integer.parseInt(sc.next()) a[i] a i Integer.parseInt(sc.next()) Integer.parseInt Integer sc.next() sc.next 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 = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        }
      } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
        if((i % 2) == 0){
          Alice = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        }
      } {
        if((i % 2) == 0){
          Alice = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        }
      } if((i % 2) == 0){
          Alice = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        } (i % 2) == 0 (i % 2) i 2 0 {
          Alice = Alice + a[i];
        } Alice = Alice + a[i] Alice Alice + a[i] Alice a[i] a i {
          Bob = Bob + a[i];
        } Bob = Bob + a[i] Bob Bob + a[i] Bob a[i] a i System.out.println(Alice - Bob) System.out.println System.out System System.out Alice - Bob Alice Bob String[] args args
import java.util.*;

//くそコード
class Main{
  public static void main(String[] args){
    try(Scanner sc = new Scanner(System.in)){
      int n = Integer.parseInt(sc.nextLine());
      //int a[] = new int[n];
      Integer a[] = new Integer[n];
      for(int i = 0; i < n; i++){
        a[i] = Integer.parseInt(sc.next());
      }
      int Alice = 0;
      int Bob = 0;
      Arrays.sort(a, Collections.reverseOrder());
      
      for(int i = 0; i < n; i++){
        if((i % 2) == 0){
          Alice = Alice + a[i];
        }else{
          Bob = Bob + a[i];
        }
      }
      System.out.println(Alice - Bob);
    }
  }
}
          
      