#include <bits/stdc++.h>
using namespace std;

int main(){
    int N, K;
    cin >> N >> K;
    vector<int> v(N);
    for(int i=0;i<N;++i)
        cin >> v[i];

    sort(begin(v), end(v));

    vector<int> sums(N);
    sums[0] = v[0];
    for(int i=1;i<N;++i){
        sums[i] = sums[i-1] + v[i];
    }

    double ans = 0;
    for(int i=0;i<N-K;++i){
        double lower_average = (double)sums[i] / (i+1);
        for(int j=i+K-2;j<N-1;++j){
            int numbers = N - j - 1;
            // cout << j << " " << numbers << endl;
            double upper_average = (sums[N-1] - sums[j]) / numbers;
            // cout << lower_average << " " << upper_average << endl;
            ans = max(ans, floor(upper_average - lower_average));
        }
    }
    cout << int(ans) << endl;
    return 0;
}