#include "bits/stdc++.h"
using namespace std;
#ifdef _DEBUG
#include "dump.hpp"
#else
#define dump(...)
#endif

#define int long long
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define all(c) begin(c),end(c)
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = 1'000'000'007;
template<class T> bool chmax(T &a, const T &b) { if (a < b) { a = b; return true; } return false; }
template<class T> bool chmin(T &a, const T &b) { if (b < a) { a = b; return true; } return false; }



signed main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int B, N; cin >> B >> N;
	vector<int> C(N); rep(i, 0, N) {
		cin >> C[i];
	}
	sort(all(C));
	dump(C);
	vector<int> sum(N + 1);
	rep(i, 0, N)sum[i + 1] = sum[i] + C[i];
	int k = INF;
	int id = -1;
	rep(i, 0, N) {
		int plus = C[i] * i - sum[i];
		int minus = sum[N] - sum[i] - C[i] * (N - i);
		dump(plus + minus);
		if (plus > B + minus)break;
		chmin(k, plus + minus);
		id = i;
	}
	dump(id);
	dump(k);
	auto g = [&](int x) {
		int plus = x * (id + 1) - sum[id + 1];
		int minus = sum[N] - sum[id + 1] - x * (N - (id + 1));
		return plus + minus;
	};
	auto f = [&](int x) {
		int plus = x * (id + 1) - sum[id + 1];
		int minus = sum[N] - sum[id + 1] - x * (N - (id + 1));
		dump(plus, minus, x);
		return plus > B + minus || plus + minus > k;
	};
	auto binarySearch = [&](int ng, int ok) {
		if (f(ng))return ng;
		while (ng + 1 < ok) {
			int m = (ng + ok) / 2;
			if (f(m))
				ok = m;
			else
				ng = m;
		}
		return ok;
	};
	if (id == N - 1) {
		cout << k << endl;
	}
	else {
		int b = binarySearch(C[id], C[id + 1]) - 1;
		dump(b);
		cout << g(b) << endl;
	}
	return 0;
}