import java.util.*;
import java.io.*;
import java.lang.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner (System.in);
		int t = sc.nextInt();
		int[] a = new int[t];
		int j = 0;
		while (t-- > 0) {
			a[j] = sc.nextInt();
			j++;
		}
		sc.close();
		Arrays.sort(a);
		int len = a.length;
		int A = 0; //for Alice
		int B = 0; //for Bob

		for (int i = 0; i<len; i+=2) {
			A+=a[i];
		}
		for (int i = 1; i<len; i+=2) {
			B+=a[i];
		}

		int result = Math.abs(A-B);
		System.out.println(result);
	}
}

/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