#include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     int k, n;     cin >> n >> k;     int x[n];     for (int i = 0; i < n; i++) {       cin >> x[i];     }     double m = -1, sum = 0;     int c = 0;     for (int i = 0; i < n; i++) {       for (int j = i; j < n; j++) {         c++;         sum += x[j];         if (c >= k && (sum / c) > m) {           m = sum / c;         }       }       c = 0;       sum = 0;     }     cout << setprecision(15) << fixed << m << endl;   }   