#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <climits>
#include <numeric>
#include <iterator>
#include <cmath>
using namespace std;

int f(vector<int> &vec, const int N, const int K) {
	sort(vec.begin(), vec.end());
	if (K == 2) {
		double max = INT_MIN;
		partial_sum(vec.begin(), vec.end(), vec.begin());
		for (int i = 0; i < N-1; ++i) {
			const double fst = vec[i] / (i+1);
			const double sec = (vec[N-1] - vec[i]) / (N-i+1);
			const double diff = sec - fst;
			if (max < diff)
				max = diff;
		}
		return ceil(max);
	} else {
		return vec.back() - vec.front();
	}
}

int main() {
	int N, K;
	vector<int> vec {};
	cin >> N >> K;
	for (int i = 0; i < N; ++i) {
		int d {};
		cin >> d;
		vec.push_back(d);
	}
	cout << f(vec, N, K) << endl;
}