import java.util.*;

public class Main {
	public static void main (String[] args) {
    	Scanner sc = new Scanner(System.in);
    	int n = sc.nextInt();
    	int[] arr = new int[n];
    	for (int i = 0; i < n; i++) {
    	    arr[i] = sc.nextInt();
    	}
    	Arrays.sort(arr);
    	long ans = 0;
    	for (int i = 0; i < n; i++) {
    	    ans += Math.abs(arr[i] - arr[n / 2]);
    	}
    	System.out.println(ans);
	}
}