You are given an array $A$ of $n$ integers. Find a subarray of length at least $k$ with the maximum mean.
### Input
- The first line contains 2 integers $n, k$.
- The second line contains $n$ integers $A_i$.
### Output
- Print the largest mean of all subarrays of length at least $k$. Your answer will be considered correct if its absolute or relative error does not exceed $10^{-3}$. In other words, your answer, $x$, will be compared to the correct answer, $y$. If $|x-y| < 10^{-3}$, then your answer will be considered correct.
### Constraints
- $1 \le k \le n \le 10^5$.
- $1 \le A_i \le 10^9$
### Example
Input:
```
5 3
1 2 3 4 5
```
Output:
```
4.000
```
