import java.util.Scanner;
import java.util.Arrays;

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 alice = 0;
		int bob = 0;
		int k = 0;
		for (int i = N - 1; i >= 0; i--) {
			if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i];
			k++;
		}
		System.out.println(Math.abs(alice - bob));
	}

} import java.util.Scanner; Scanner java.util import java.util.Arrays; Arrays 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 alice = 0;
		int bob = 0;
		int k = 0;
		for (int i = N - 1; i >= 0; i--) {
			if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i];
			k++;
		}
		System.out.println(Math.abs(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();
		}
		Arrays.sort(a);
		int alice = 0;
		int bob = 0;
		int k = 0;
		for (int i = N - 1; i >= 0; i--) {
			if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i];
			k++;
		}
		System.out.println(Math.abs(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();
		}
		Arrays.sort(a);
		int alice = 0;
		int bob = 0;
		int k = 0;
		for (int i = N - 1; i >= 0; i--) {
			if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i];
			k++;
		}
		System.out.println(Math.abs(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 Arrays.sort(a) Arrays.sort Arrays a int alice = 0; alice 0 int bob = 0; bob 0 int k = 0; k 0 for (int i = N - 1; i >= 0; i--) {
			if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i];
			k++;
		} int i = N - 1; int i = N - 1; i N - 1 N 1 i >= 0 i 0 i-- i-- i {
			if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i];
			k++;
		} {
			if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i];
			k++;
		} if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i]; k % 2 == 0 k % 2 k 2 0 alice += a[i] alice a[i] a i bob += a[i] bob a[i] a i k++ k System.out.println(Math.abs(alice - bob)) System.out.println System.out System System.out Math.abs(alice - bob) Math.abs Math 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();
		}
		Arrays.sort(a);
		int alice = 0;
		int bob = 0;
		int k = 0;
		for (int i = N - 1; i >= 0; i--) {
			if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i];
			k++;
		}
		System.out.println(Math.abs(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();
		}
		Arrays.sort(a);
		int alice = 0;
		int bob = 0;
		int k = 0;
		for (int i = N - 1; i >= 0; i--) {
			if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i];
			k++;
		}
		System.out.println(Math.abs(alice - bob));
	}

} Main
import java.util.Scanner;
import java.util.Arrays;

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 alice = 0;
		int bob = 0;
		int k = 0;
		for (int i = N - 1; i >= 0; i--) {
			if (k % 2 == 0)
				alice += a[i];
			else
				bob += a[i];
			k++;
		}
		System.out.println(Math.abs(alice - bob));
	}

}
