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 void main(String[] args) {
		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);

	}

}