import java.util.Arrays;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) throws Exception{
		Scanner scan=new Scanner(System.in);
		int a=scan.nextInt();
		int bob=0;
		int Alice=0;
		int b[]=new int[a];
		for(int i=0;i!=a;i++) {
			b[i]=scan.nextInt();
		}
		Arrays.sort(b);
		for(int i=0;i!=a;i++) {
			if(i%2==0) {
				bob+=b[i];
			}
			else {
				Alice+=b[i];
			}
		}
		System.out.println(Math.abs(Alice-bob));
	}
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz