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 + 1];
		int alice = 0, bob = 0;

		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		
		Arrays.sort(a);
		
		for (int i = n; i > 0; i-=2) {
			alice += a[i];
			if (i != 0)
			bob += a[i-1];
		}

		System.out.println(Math.abs(alice - bob));

		sc.close();
	}
} 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 + 1];
		int alice = 0, bob = 0;

		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		
		Arrays.sort(a);
		
		for (int i = n; i > 0; i-=2) {
			alice += a[i];
			if (i != 0)
			bob += a[i-1];
		}

		System.out.println(Math.abs(alice - bob));

		sc.close();
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner((System.in));
		int n = sc.nextInt();
		int[] a = new int[n + 1];
		int alice = 0, bob = 0;

		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		
		Arrays.sort(a);
		
		for (int i = n; i > 0; i-=2) {
			alice += a[i];
			if (i != 0)
			bob += a[i-1];
		}

		System.out.println(Math.abs(alice - bob));

		sc.close();
	} main {
		Scanner sc = new Scanner((System.in));
		int n = sc.nextInt();
		int[] a = new int[n + 1];
		int alice = 0, bob = 0;

		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		
		Arrays.sort(a);
		
		for (int i = n; i > 0; i-=2) {
			alice += a[i];
			if (i != 0)
			bob += a[i-1];
		}

		System.out.println(Math.abs(alice - bob));

		sc.close();
	} 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 + 1]; a new int[n + 1] n + 1 n 1 int alice = 0 alice 0 bob = 0; bob 0 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 for (int i = n; i > 0; i-=2) {
			alice += a[i];
			if (i != 0)
			bob += a[i-1];
		} int i = n; int i = n; i n i > 0 i 0 i-=2 i-=2 i 2 {
			alice += a[i];
			if (i != 0)
			bob += a[i-1];
		} {
			alice += a[i];
			if (i != 0)
			bob += a[i-1];
		} alice += a[i] alice a[i] a i if (i != 0)
			bob += a[i-1]; i != 0 i 0 bob += a[i-1] bob a[i-1] a i-1 i 1 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 sc.close() sc.close sc 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 + 1];
		int alice = 0, bob = 0;

		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		
		Arrays.sort(a);
		
		for (int i = n; i > 0; i-=2) {
			alice += a[i];
			if (i != 0)
			bob += a[i-1];
		}

		System.out.println(Math.abs(alice - bob));

		sc.close();
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner((System.in));
		int n = sc.nextInt();
		int[] a = new int[n + 1];
		int alice = 0, bob = 0;

		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		
		Arrays.sort(a);
		
		for (int i = n; i > 0; i-=2) {
			alice += a[i];
			if (i != 0)
			bob += a[i-1];
		}

		System.out.println(Math.abs(alice - bob));

		sc.close();
	}
} 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 + 1];
		int alice = 0, bob = 0;

		for (int i = 0; i < n; i++) {
			a[i] = sc.nextInt();
		}
		
		Arrays.sort(a);
		
		for (int i = n; i > 0; i-=2) {
			alice += a[i];
			if (i != 0)
			bob += a[i-1];
		}

		System.out.println(Math.abs(alice - bob));

		sc.close();
	}
}
