import java.util.Scanner;


public class Main {

    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int b = sc.nextInt();
        int n = sc.nextInt();
        int[] c = new int[n];
        int ave = 0;
        for (int i = 0; i < c.length; i++) {
            c[i] = sc.nextInt();
            ave+=c[i];
        }
        ave /= n;
        long ans = Long.MAX_VALUE;
        for(int i = Math.max(0, ave-100000); i< ave+100000;i++){
            int d = i;
            int bb = b;
            long cnt = 0;
            for (int j = 0; j < c.length; j++) {
                cnt += Math.abs(c[j]-d);
                bb -= d-c[j];
            }
//            System.out.println(i+" "+cnt +" "+ ans);
            if(bb < 0)continue;
            ans = Math.min(ans, cnt);   
        }
        System.out.println(ans);
    }

}