프로그램 명: coci_prosjek2(special judge)

제한시간: 1 초

You are given an array of N integers. Find a consecutive subsequence of numbers of the length at least K that has the maximal possible average.

Please note: the average of a subsequence is the sum of all the numbers in the subsequence divided by its length.

The first line of input contains two integers N (1 <= N <= 3*10^5) and K (1 <= K <= N).
The second line of input contains N integers ai (1 <= ai <= 10^6).

The first and only line of output must contain the maximal possible average. An absolute deviation of ±0.001 from the official solution is permitted.

입력

4 1
1 2 3 4

출력

4.000000

입력

4 2
2 4 3 4

출력

3.666666

입력

6 3
7 1 2 1 3 6

출력

3.333333

출처:2013-2014 contest7 5/6