import java.util.*;

public class Main {
    public static void main(String[]  args) {
        Scanner sc = new Scanner(System.in);
        long total = sc.nextInt();
        int n = sc.nextInt();
        int[] arr = new int[n];
        for (int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
            total += arr[i];
        }
        long left = 0;
        long right = total / n;
        boolean isRight = false;
        while (right - left > 2) {
            long m1 = (left * 2 + right) / 3;
            long m2 = (left + right * 2) / 3;
            if (calc((int)m1, arr) <= calc((int)m2, arr)) {
                right = m2;
                isRight = false;
            } else {
                isRight = true;
                left = m1;
            }
        }
        System.out.println(Math.min(Math.min(calc((int)right, arr), calc((int)left, arr)), Math.min(calc((int)((left * 2 + right) / 3), arr), calc((int)((left + right * 2) / 3), arr))));
    }
    
    static int calc(int x, int[] arr) {
        int ans = 0;
        for (int y : arr) {
            ans += Math.abs(x - y);
        }
        return ans;
    }
}