#include <bits/stdc++.h>   using namespace std;   const int maxn = 5000 + 10;   int main() {     int n, k;     int a[maxn];     scanf( %d%d , &n, &k);     for (int i = 0; i < n; i++) scanf( %d , &a[i]);     int sum = 0;     int maxs = 0;     double maxa = 0;     for (int i = k; i <= n; i++) {       for (int j = 0; j < i; j++) sum += a[j];       maxs = sum;       for (int j = 1; j < n - i + 1; j++) {         sum = sum - a[j - 1] + a[j + i - 1];         maxs = max(maxs, sum);       }       double a = maxs * 1.0 / i;       maxa = max(maxa, a);       sum = 0;     }     printf( %lf n , maxa);     return 0;   }   