import java.util.*;

public class Main{

	public static void main(String[]args){
		Scanner sc = new Scanner(System.in);

		int n=sc.nextInt();
		int a[]=new int[n];
		for(int i=0;i<n;i++){
			a[i]=sc.nextInt();
		}

		int Alice=0;
		int Bob=0;

		Arrays.sort(a);

		for(int i=n-1;i>=0;i--){
			if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}
		}


		System.out.println(Alice-Bob);


	}
} import java.util.*; util.* java public class Main{

	public static void main(String[]args){
		Scanner sc = new Scanner(System.in);

		int n=sc.nextInt();
		int a[]=new int[n];
		for(int i=0;i<n;i++){
			a[i]=sc.nextInt();
		}

		int Alice=0;
		int Bob=0;

		Arrays.sort(a);

		for(int i=n-1;i>=0;i--){
			if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}
		}


		System.out.println(Alice-Bob);


	}
} Main public static void main(String[]args){
		Scanner sc = new Scanner(System.in);

		int n=sc.nextInt();
		int a[]=new int[n];
		for(int i=0;i<n;i++){
			a[i]=sc.nextInt();
		}

		int Alice=0;
		int Bob=0;

		Arrays.sort(a);

		for(int i=n-1;i>=0;i--){
			if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}
		}


		System.out.println(Alice-Bob);


	} main {
		Scanner sc = new Scanner(System.in);

		int n=sc.nextInt();
		int a[]=new int[n];
		for(int i=0;i<n;i++){
			a[i]=sc.nextInt();
		}

		int Alice=0;
		int Bob=0;

		Arrays.sort(a);

		for(int i=n-1;i>=0;i--){
			if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}
		}


		System.out.println(Alice-Bob);


	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n=sc.nextInt(); n sc.nextInt() sc.nextInt sc int a[]=new int[n]; a new int[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]=sc.nextInt() a[i] a i sc.nextInt() sc.nextInt sc int Alice=0; Alice 0 int Bob=0; Bob 0 Arrays.sort(a) Arrays.sort Arrays a for(int i=n-1;i>=0;i--){
			if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}
		} int i=n-1; int i=n-1; i n-1 n 1 i>=0 i 0 i-- i-- i {
			if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}
		} {
			if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}
		} if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			} (n-1)%2==0 (n-1)%2 (n-1) n 1 2 0 {
				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 {
				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(Alice-Bob) System.out.println System.out System System.out Alice-Bob Alice Bob String[]args args public class Main{

	public static void main(String[]args){
		Scanner sc = new Scanner(System.in);

		int n=sc.nextInt();
		int a[]=new int[n];
		for(int i=0;i<n;i++){
			a[i]=sc.nextInt();
		}

		int Alice=0;
		int Bob=0;

		Arrays.sort(a);

		for(int i=n-1;i>=0;i--){
			if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}
		}


		System.out.println(Alice-Bob);


	}
} public class Main{

	public static void main(String[]args){
		Scanner sc = new Scanner(System.in);

		int n=sc.nextInt();
		int a[]=new int[n];
		for(int i=0;i<n;i++){
			a[i]=sc.nextInt();
		}

		int Alice=0;
		int Bob=0;

		Arrays.sort(a);

		for(int i=n-1;i>=0;i--){
			if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}
		}


		System.out.println(Alice-Bob);


	}
} Main
import java.util.*;

public class Main{

	public static void main(String[]args){
		Scanner sc = new Scanner(System.in);

		int n=sc.nextInt();
		int a[]=new int[n];
		for(int i=0;i<n;i++){
			a[i]=sc.nextInt();
		}

		int Alice=0;
		int Bob=0;

		Arrays.sort(a);

		for(int i=n-1;i>=0;i--){
			if((n-1)%2==0){
				if(i%2==0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}else{
				if(i%2!=0){
					Alice+=a[i];
				}else{
					Bob+=a[i];
				}
			}
		}


		System.out.println(Alice-Bob);


	}
}
