import java.util.*;
import java.util.Collections;
import java.util.ArrayList;

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

        int N = sc.nextInt();
        int ans = 0;
        ArrayList<Integer> list = new ArrayList<Integer>();

        for(int i=0; i<N; i++){
            list.add(sc.nextInt());
        }

        Collections.sort(list);

        if(list.get(N/2)!=list.get(N/2-1)){
            for(int i=list.get(N/2-1)+1; i<=list.get(N/2); i++){
                ans += 1;
            }
            System.out.println(ans);
        }
        else{
            System.out.println(0);
        }
    }
} import java.util.*; util.* java import java.util.Collections; Collections java.util import java.util.ArrayList; ArrayList java.util public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int ans = 0;
        ArrayList<Integer> list = new ArrayList<Integer>();

        for(int i=0; i<N; i++){
            list.add(sc.nextInt());
        }

        Collections.sort(list);

        if(list.get(N/2)!=list.get(N/2-1)){
            for(int i=list.get(N/2-1)+1; i<=list.get(N/2); i++){
                ans += 1;
            }
            System.out.println(ans);
        }
        else{
            System.out.println(0);
        }
    }
} Main public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int ans = 0;
        ArrayList<Integer> list = new ArrayList<Integer>();

        for(int i=0; i<N; i++){
            list.add(sc.nextInt());
        }

        Collections.sort(list);

        if(list.get(N/2)!=list.get(N/2-1)){
            for(int i=list.get(N/2-1)+1; i<=list.get(N/2); i++){
                ans += 1;
            }
            System.out.println(ans);
        }
        else{
            System.out.println(0);
        }
    } main {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int ans = 0;
        ArrayList<Integer> list = new ArrayList<Integer>();

        for(int i=0; i<N; i++){
            list.add(sc.nextInt());
        }

        Collections.sort(list);

        if(list.get(N/2)!=list.get(N/2-1)){
            for(int i=list.get(N/2-1)+1; i<=list.get(N/2); i++){
                ans += 1;
            }
            System.out.println(ans);
        }
        else{
            System.out.println(0);
        }
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int ans = 0; ans 0 ArrayList<Integer> list = new ArrayList<Integer>(); list new ArrayList<Integer>() for(int i=0; i<N; i++){
            list.add(sc.nextInt());
        } int i=0; int i=0; i 0 i<N i N i++ i++ i {
            list.add(sc.nextInt());
        } {
            list.add(sc.nextInt());
        } list.add(sc.nextInt()) list.add list sc.nextInt() sc.nextInt sc Collections.sort(list) Collections.sort Collections list if(list.get(N/2)!=list.get(N/2-1)){
            for(int i=list.get(N/2-1)+1; i<=list.get(N/2); i++){
                ans += 1;
            }
            System.out.println(ans);
        }
        else{
            System.out.println(0);
        } list.get(N/2)!=list.get(N/2-1) list.get(N/2) list.get list N/2 N 2 list.get(N/2-1) list.get list N/2-1 N/2 N 2 1 {
            for(int i=list.get(N/2-1)+1; i<=list.get(N/2); i++){
                ans += 1;
            }
            System.out.println(ans);
        } for(int i=list.get(N/2-1)+1; i<=list.get(N/2); i++){
                ans += 1;
            } int i=list.get(N/2-1)+1; int i=list.get(N/2-1)+1; i list.get(N/2-1)+1 list.get(N/2-1) list.get list N/2-1 N/2 N 2 1 1 i<=list.get(N/2) i list.get(N/2) list.get list N/2 N 2 i++ i++ i {
                ans += 1;
            } {
                ans += 1;
            } ans += 1 ans 1 System.out.println(ans) System.out.println System.out System System.out ans {
            System.out.println(0);
        } System.out.println(0) System.out.println System.out System System.out 0 String[] args args public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int ans = 0;
        ArrayList<Integer> list = new ArrayList<Integer>();

        for(int i=0; i<N; i++){
            list.add(sc.nextInt());
        }

        Collections.sort(list);

        if(list.get(N/2)!=list.get(N/2-1)){
            for(int i=list.get(N/2-1)+1; i<=list.get(N/2); i++){
                ans += 1;
            }
            System.out.println(ans);
        }
        else{
            System.out.println(0);
        }
    }
} public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        int ans = 0;
        ArrayList<Integer> list = new ArrayList<Integer>();

        for(int i=0; i<N; i++){
            list.add(sc.nextInt());
        }

        Collections.sort(list);

        if(list.get(N/2)!=list.get(N/2-1)){
            for(int i=list.get(N/2-1)+1; i<=list.get(N/2); i++){
                ans += 1;
            }
            System.out.println(ans);
        }
        else{
            System.out.println(0);
        }
    }
} Main
import java.util.*;
import java.util.Collections;
import java.util.ArrayList;

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

        int N = sc.nextInt();
        int ans = 0;
        ArrayList<Integer> list = new ArrayList<Integer>();

        for(int i=0; i<N; i++){
            list.add(sc.nextInt());
        }

        Collections.sort(list);

        if(list.get(N/2)!=list.get(N/2-1)){
            for(int i=list.get(N/2-1)+1; i<=list.get(N/2); i++){
                ans += 1;
            }
            System.out.println(ans);
        }
        else{
            System.out.println(0);
        }
    }
}