import java.util.Arrays;
import java.util.Scanner;
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();
    }
    Arrays.sort(a);

    int x = 0;
    int y = 0;
    for(int i=0; i<N; i++) {
    	if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	}
    	}
    System.out.println(Math.abs(x-y));
    }
} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner 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();
    }
    Arrays.sort(a);

    int x = 0;
    int y = 0;
    for(int i=0; i<N; i++) {
    	if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	}
    	}
    System.out.println(Math.abs(x-y));
    }
} 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();
    }
    Arrays.sort(a);

    int x = 0;
    int y = 0;
    for(int i=0; i<N; i++) {
    	if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	}
    	}
    System.out.println(Math.abs(x-y));
    } 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();
    }
    Arrays.sort(a);

    int x = 0;
    int y = 0;
    for(int i=0; i<N; i++) {
    	if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	}
    	}
    System.out.println(Math.abs(x-y));
    } 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 Arrays.sort(a) Arrays.sort Arrays a int x = 0; x 0 int y = 0; y 0 for(int i=0; i<N; i++) {
    	if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	}
    	} int i=0; int i=0; i 0 i<N i N i++ i++ i {
    	if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	}
    	} {
    	if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	}
    	} if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	} i%2==0 i%2 i 2 0 {
    		x += a[i];
    	} x += a[i] x a[i] a i {
    		y += a[i];
    	} y += a[i] y a[i] a i System.out.println(Math.abs(x-y)) System.out.println System.out System System.out Math.abs(x-y) Math.abs Math x-y x y 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();
    }
    Arrays.sort(a);

    int x = 0;
    int y = 0;
    for(int i=0; i<N; i++) {
    	if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	}
    	}
    System.out.println(Math.abs(x-y));
    }
} 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();
    }
    Arrays.sort(a);

    int x = 0;
    int y = 0;
    for(int i=0; i<N; i++) {
    	if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	}
    	}
    System.out.println(Math.abs(x-y));
    }
} Main
import java.util.Arrays;
import java.util.Scanner;
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();
    }
    Arrays.sort(a);

    int x = 0;
    int y = 0;
    for(int i=0; i<N; i++) {
    	if(i%2==0) {
    		x += a[i];
    	}else {
    		y += a[i];
    	}
    	}
    System.out.println(Math.abs(x-y));
    }
}