import java.util.Arrays;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
int res = 0 ;
int []b = new int[a];
for (int i = 0; i <a; i++) {
b[i]= sc.nextInt();
}
//sort
Arrays.sort(b);
//judgement
//中位数到各点的距离之和即为最短路径
for (int i = 0; i <a ; i++) {
res+=Math.abs(b[i]-b[a/2]);
}
System.out.println(res);
}
}