#include <stdio.h>
#include <math.h>

int main(void) {
	long long int i, j;
	long long int b, n, c[10];
	long long int sum, num, count, min_count;
	scanf("%lld", &b);
	sum = 0;
	scanf("%lld", &n);
	for(i = 0;i < n;i++){
		scanf("%lld", &c[i]);
		sum += c[i];
	}
	min_count = -1;
	for(j = 0;j <= b;j++){
		num = (sum + j) / n;
		count = 0;
		for(i = 0;i < n;i++){
			count += abs(c[i] - num);
		}
		if(min_count == -1 || min_count > count)min_count = count;
		else break;
	}
	printf("%d\n", min_count);

    return 0;
}