import java.util.Scanner;
public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int hok;
        int n = sc.nextInt();
        int num[] = new int[n];
        for(int i = 1;i <= n; i++){
            num[i-1] = sc.nextInt();
        }
        for(int j = 0; j <= n; j++){
            for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            }
        }
        int a = 0,b = 0,s;
        for(int i = 1;i <= n/2; i++){
        a = a + num[2 * i - 2];
        b = b + num[2 * i - 1];
        }
        if(n % 2 == 1){
            a = a + num[n-1];
        }
        s = a - b;
        if(s < 0){
            s = -s;
        }
        System.out.println(s);
        sc.close();
    }
} import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int hok;
        int n = sc.nextInt();
        int num[] = new int[n];
        for(int i = 1;i <= n; i++){
            num[i-1] = sc.nextInt();
        }
        for(int j = 0; j <= n; j++){
            for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            }
        }
        int a = 0,b = 0,s;
        for(int i = 1;i <= n/2; i++){
        a = a + num[2 * i - 2];
        b = b + num[2 * i - 1];
        }
        if(n % 2 == 1){
            a = a + num[n-1];
        }
        s = a - b;
        if(s < 0){
            s = -s;
        }
        System.out.println(s);
        sc.close();
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int hok;
        int n = sc.nextInt();
        int num[] = new int[n];
        for(int i = 1;i <= n; i++){
            num[i-1] = sc.nextInt();
        }
        for(int j = 0; j <= n; j++){
            for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            }
        }
        int a = 0,b = 0,s;
        for(int i = 1;i <= n/2; i++){
        a = a + num[2 * i - 2];
        b = b + num[2 * i - 1];
        }
        if(n % 2 == 1){
            a = a + num[n-1];
        }
        s = a - b;
        if(s < 0){
            s = -s;
        }
        System.out.println(s);
        sc.close();
    } main {
        Scanner sc = new Scanner(System.in);
        int hok;
        int n = sc.nextInt();
        int num[] = new int[n];
        for(int i = 1;i <= n; i++){
            num[i-1] = sc.nextInt();
        }
        for(int j = 0; j <= n; j++){
            for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            }
        }
        int a = 0,b = 0,s;
        for(int i = 1;i <= n/2; i++){
        a = a + num[2 * i - 2];
        b = b + num[2 * i - 1];
        }
        if(n % 2 == 1){
            a = a + num[n-1];
        }
        s = a - b;
        if(s < 0){
            s = -s;
        }
        System.out.println(s);
        sc.close();
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int hok; hok int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc int num[] = new int[n]; num new int[n] n for(int i = 1;i <= n; i++){
            num[i-1] = sc.nextInt();
        } int i = 1; int i = 1; i 1 i <= n i n i++ i++ i {
            num[i-1] = sc.nextInt();
        } {
            num[i-1] = sc.nextInt();
        } num[i-1] = sc.nextInt() num[i-1] num i-1 i 1 sc.nextInt() sc.nextInt sc for(int j = 0; j <= n; j++){
            for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            }
        } int j = 0; int j = 0; j 0 j <= n j n j++ j++ j {
            for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            }
        } {
            for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            }
        } for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            } int i = 0; int i = 0; i 0 i < n - 1 i n - 1 n 1 i++ i++ i {
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            } {
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            } if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                } num[i] < num[i + 1] num[i] num i num[i + 1] num i + 1 i 1 {
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                } hok = num[i] hok num[i] num i num[i] = num[i + 1] num[i] num i num[i + 1] num i + 1 i 1 num[i + 1] = hok num[i + 1] num i + 1 i 1 hok int a = 0 a 0 b = 0 b 0 s; s for(int i = 1;i <= n/2; i++){
        a = a + num[2 * i - 2];
        b = b + num[2 * i - 1];
        } int i = 1; int i = 1; i 1 i <= n/2 i n/2 n 2 i++ i++ i {
        a = a + num[2 * i - 2];
        b = b + num[2 * i - 1];
        } {
        a = a + num[2 * i - 2];
        b = b + num[2 * i - 1];
        } a = a + num[2 * i - 2] a a + num[2 * i - 2] a num[2 * i - 2] num 2 * i - 2 2 * i 2 i 2 b = b + num[2 * i - 1] b b + num[2 * i - 1] b num[2 * i - 1] num 2 * i - 1 2 * i 2 i 1 if(n % 2 == 1){
            a = a + num[n-1];
        } n % 2 == 1 n % 2 n 2 1 {
            a = a + num[n-1];
        } a = a + num[n-1] a a + num[n-1] a num[n-1] num n-1 n 1 s = a - b s a - b a b if(s < 0){
            s = -s;
        } s < 0 s 0 {
            s = -s;
        } s = -s s -s s System.out.println(s) System.out.println System.out System System.out s sc.close() sc.close sc String[] args args public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int hok;
        int n = sc.nextInt();
        int num[] = new int[n];
        for(int i = 1;i <= n; i++){
            num[i-1] = sc.nextInt();
        }
        for(int j = 0; j <= n; j++){
            for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            }
        }
        int a = 0,b = 0,s;
        for(int i = 1;i <= n/2; i++){
        a = a + num[2 * i - 2];
        b = b + num[2 * i - 1];
        }
        if(n % 2 == 1){
            a = a + num[n-1];
        }
        s = a - b;
        if(s < 0){
            s = -s;
        }
        System.out.println(s);
        sc.close();
    }
} public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int hok;
        int n = sc.nextInt();
        int num[] = new int[n];
        for(int i = 1;i <= n; i++){
            num[i-1] = sc.nextInt();
        }
        for(int j = 0; j <= n; j++){
            for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            }
        }
        int a = 0,b = 0,s;
        for(int i = 1;i <= n/2; i++){
        a = a + num[2 * i - 2];
        b = b + num[2 * i - 1];
        }
        if(n % 2 == 1){
            a = a + num[n-1];
        }
        s = a - b;
        if(s < 0){
            s = -s;
        }
        System.out.println(s);
        sc.close();
    }
} Main
import java.util.Scanner;
public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int hok;
        int n = sc.nextInt();
        int num[] = new int[n];
        for(int i = 1;i <= n; i++){
            num[i-1] = sc.nextInt();
        }
        for(int j = 0; j <= n; j++){
            for(int i = 0; i < n - 1; i++){
                if(num[i] < num[i + 1]){
                    hok = num[i];
                    num[i] = num[i + 1];
                    num[i + 1] = hok;
                }
            }
        }
        int a = 0,b = 0,s;
        for(int i = 1;i <= n/2; i++){
        a = a + num[2 * i - 2];
        b = b + num[2 * i - 1];
        }
        if(n % 2 == 1){
            a = a + num[n-1];
        }
        s = a - b;
        if(s < 0){
            s = -s;
        }
        System.out.println(s);
        sc.close();
    }
}