import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner koko = new Scanner(System.in);
        long b = koko.nextLong();
        int n = koko.nextInt();
        long[] c = new long[n];
        long total=0;
        for(int i=0; i<n; i++){
        	c[i]=koko.nextInt();
        	total = total+c[i];
        }
        total = total + b;
        int max = (int)Math.floor(total/n);
        long[] move = new long[max+1];
        for(int i=0; i<max+1; i++){
        	move[i]=0;
        	for(int j=0; j<n; j++){
        	    move[i] = move[i]+Math.abs(c[j]-i);
            }
        }
        long movemin = move[0];
        for(int i=0; i<max+1; i++){
        	movemin = Math.min(movemin, move[i]);
        }
        System.out.println(movemin);
    }
}