import 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);
long sum=0;
for(int i=0;i<n;i){
sum=sum+Math.abs(a[i]-a[n/2]);
}
System.out.println(sum);
}
}