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

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		Integer[] a = new Integer[n];
		for (int i = 0; i < a.length; i++) {
			a[i] = sc.nextInt();
		}
		Arrays.sort(a, Comparator.reverseOrder());

		int Alice = 0;
		int Bob = 0;
		int turn = 1;
		for (int i = 0; i < a.length; i++) {
			if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			}
			turn *= -1;
		}

		System.out.println(Alice - Bob);

		sc.close();
	}
} import java.util.Arrays; Arrays java.util import java.util.Comparator; Comparator 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();
		Integer[] a = new Integer[n];
		for (int i = 0; i < a.length; i++) {
			a[i] = sc.nextInt();
		}
		Arrays.sort(a, Comparator.reverseOrder());

		int Alice = 0;
		int Bob = 0;
		int turn = 1;
		for (int i = 0; i < a.length; i++) {
			if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			}
			turn *= -1;
		}

		System.out.println(Alice - Bob);

		sc.close();
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		Integer[] a = new Integer[n];
		for (int i = 0; i < a.length; i++) {
			a[i] = sc.nextInt();
		}
		Arrays.sort(a, Comparator.reverseOrder());

		int Alice = 0;
		int Bob = 0;
		int turn = 1;
		for (int i = 0; i < a.length; i++) {
			if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			}
			turn *= -1;
		}

		System.out.println(Alice - Bob);

		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		Integer[] a = new Integer[n];
		for (int i = 0; i < a.length; i++) {
			a[i] = sc.nextInt();
		}
		Arrays.sort(a, Comparator.reverseOrder());

		int Alice = 0;
		int Bob = 0;
		int turn = 1;
		for (int i = 0; i < a.length; i++) {
			if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			}
			turn *= -1;
		}

		System.out.println(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 Integer[] a = new Integer[n]; a new Integer[n] n for (int i = 0; i < a.length; i++) {
			a[i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < a.length i a.length a a.length 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, Comparator.reverseOrder()) Arrays.sort Arrays a Comparator.reverseOrder() Comparator.reverseOrder Comparator int Alice = 0; Alice 0 int Bob = 0; Bob 0 int turn = 1; turn 1 for (int i = 0; i < a.length; i++) {
			if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			}
			turn *= -1;
		} int i = 0; int i = 0; i 0 i < a.length i a.length a a.length i++ i++ i {
			if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			}
			turn *= -1;
		} {
			if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			}
			turn *= -1;
		} if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			} turn > 0 turn 0 {
				Alice += a[i];
			} Alice += a[i] Alice a[i] a i {
				Bob += a[i];
			} Bob += a[i] Bob a[i] a i turn *= -1 turn -1 1 System.out.println(Alice - Bob) System.out.println System.out System System.out 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();
		Integer[] a = new Integer[n];
		for (int i = 0; i < a.length; i++) {
			a[i] = sc.nextInt();
		}
		Arrays.sort(a, Comparator.reverseOrder());

		int Alice = 0;
		int Bob = 0;
		int turn = 1;
		for (int i = 0; i < a.length; i++) {
			if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			}
			turn *= -1;
		}

		System.out.println(Alice - Bob);

		sc.close();
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		Integer[] a = new Integer[n];
		for (int i = 0; i < a.length; i++) {
			a[i] = sc.nextInt();
		}
		Arrays.sort(a, Comparator.reverseOrder());

		int Alice = 0;
		int Bob = 0;
		int turn = 1;
		for (int i = 0; i < a.length; i++) {
			if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			}
			turn *= -1;
		}

		System.out.println(Alice - Bob);

		sc.close();
	}
} Main
import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		Integer[] a = new Integer[n];
		for (int i = 0; i < a.length; i++) {
			a[i] = sc.nextInt();
		}
		Arrays.sort(a, Comparator.reverseOrder());

		int Alice = 0;
		int Bob = 0;
		int turn = 1;
		for (int i = 0; i < a.length; i++) {
			if (turn > 0) {
				Alice += a[i];
			} else {
				Bob += a[i];
			}
			turn *= -1;
		}

		System.out.println(Alice - Bob);

		sc.close();
	}
}
