#include<iostream>
#include<vector>
#include<numeric>

int main() {
	int box_num, having_candy_num;
	std::cin >> having_candy_num >> box_num;

	std::vector<long long> boxes(box_num);
	for (int i = 0; i < box_num; i++) std::cin >> boxes[i];

	long long ave = std::accumulate(boxes.begin(), boxes.end(), 0) / box_num;

	long long count = 0;
	for (size_t i = 0; i < boxes.size(); i++) {
		if (boxes[i] > ave) {
			for (size_t j = 0; j < boxes.size(); j++) {
				while(boxes[i] != ave && boxes[j] < ave){
					boxes[i]--;
					boxes[j]++;
					count += 2;
				}
			}
			if (boxes[i] != ave) count += boxes[i] - ave;
		} else if(boxes[i] < ave) {
			for (size_t j = 0; j < boxes.size(); j++) {
				while (boxes[i] != ave && boxes[j] > ave) {
					boxes[i]++;
					boxes[j]--;
					count+=2;
				}
			}
			if (boxes[i] != ave) count += ave - boxes[i];
		}
	}

	std::cout << count << std::endl;
	return 0;
}