import java.util.Arrays;
import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.Scanner;

public class Main {

	void run() {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		long[] Y = new long[N];
		for (int i = 0; i < N; ++i)
			Y[i] = sc.nextLong();
		Arrays.sort(Y);
		long ans = 0;
		for (int i = 0; i < N; ++i)
			ans += Math.abs(Y[i] - Y[N / 2]);
		System.out.println(ans);
	}

	void tr(Object... objects) {
		System.out.println(Arrays.deepToString(objects));
	}

	public static void main(String[] args) {
		new Main().run();
	}
}