import java.util.*;

class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        Integer num[] = new Integer[N];
        int alice = 0;
        int bob = 0;
        for(int i=0;i<N;i++){num[i]=sc.nextInt();}
        Arrays.sort(num);
        for(int i=N-1;i!=-1;i--){
            if(i%2==0){alice+=num[i];}
            else{bob+=num[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