import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Random;
import java.util.Scanner;
import java.util.Set;

public class Main {
	
	public static long solve_smart(long B, int N, long[] arr){
		long score = Long.MAX_VALUE;
		for(int pos = 0; pos < N; pos++){
			long benefit = B, current_score = 0;
			
			for(int i = 0; i < N; i++){
				benefit += (arr[i] - arr[pos]);
				current_score += Math.abs(arr[i] - arr[pos]);
			}
			if(benefit < 0){ continue; }
			
			score = Math.min(score, current_score);
		}
		
		{
			final long max = (Arrays.stream(arr).sum() + B) / N;
			System.out.println(max);
			long current_score = 0;
			for(int i = 0; i < N; i++){
				current_score += Math.abs(arr[i] - max);
			}
			
			score = Math.min(score , current_score);
		}
		
		return score;
	}
	
	public static long solve_naive(long B, int N, long[] arr){
		//System.out.println(Arrays.toString(arr));
		final long max = Arrays.stream(arr).max().getAsLong();
		
		long score = Long.MAX_VALUE, min_cur = -1;
		for(long cur = 0; cur <= max; cur++){
			long benefit = B, current_score = 0;
			
			for(int i = 0; i < N; i++){
				benefit += (arr[i] - cur);
				current_score += Math.abs(arr[i] - cur);
			}
			if(benefit < 0){ continue; }
			
			if(score > current_score){
				score = current_score;
				min_cur = cur;
			}
			score = Math.min(score, current_score);
		}
		
		System.out.println(B + " " + N + " " + Arrays.toString(arr) + " " + min_cur + " " + Arrays.stream(arr).average() + " "  + score);
		
		return score;
	}
	
	public static void check(){
		Random rnd = new Random();
		
		while(true){
			final long B = rnd.nextInt(1000);
			final int N = rnd.nextInt(9) + 1;
			long[] arr = new long[N];
			for(int i = 0; i < N; i++){
				arr[i] = rnd.nextInt(100);
			}
			
			final long smart = solve_smart(B, N, arr);
			final long naive = solve_naive(B, N, arr);
			
			if(smart != naive){
				System.out.println(">>>> naive = " + naive + ", smart = " + smart);
				//
			}
			
		}
	}
	
	public static void main(String[] args) {
		//check();
		
		Scanner sc = new Scanner(System.in);

		final long B = sc.nextLong();
		final int N = sc.nextInt();
		
		long[] arr = new long[N];
		for(int i = 0; i < N; i++){
			final long c = sc.nextLong();
		
			arr[i] = c;
		}
		
		Arrays.sort(arr);
		
		long score = Long.MAX_VALUE;
		for(int pos = 0; pos < N; pos++){
			long benefit = B, current_score = 0;
			
			for(int i = 0; i < N; i++){
				benefit += (arr[i] - arr[pos]);
				current_score += Math.abs(arr[i] - arr[pos]);
			}
			if(benefit < 0){ continue; }
			
			score = Math.min(score, current_score);
		}
		
		{
			final long max = (Arrays.stream(arr).sum() + B) / N;
			
			long current_score = 0;
			for(int i = 0; i < N; i++){
				current_score += Math.abs(arr[i] - max);
			}
			
			score = Math.min(score , current_score);
		}
		
		System.out.println(score);

	}

}