http://codeforces.com/contest/1133/problem/C
time limit per test 2 seconds
memory limit per test 256 megabytes
inputstandard input
outputstandard output
You are a coach at your local university. There are $n$ students under your supervision, the programming skill of the i-th student is $a_i$.
You have to create a team for a new programming competition. As you know, the more students some team has the more probable its victory is! So you have to create a team with the maximum number of students. But you also know that a team should be balanced. It means that the programming skill of each pair of students in a created team should differ by no more than 5.
Your task is to report the maximum possible number of students in a balanced team.
Input
The first line of the input contains one integer $n$($1≤n≤2⋅10^5$) — the number of students.
The second line of the input contains $n$ integers $a_1,a_2,…,a_n$($1≤a_i≤10^9$), where $a_i$ is a programming skill of the i-th student.
Output
Print one integer — the maximum possible number of students in a balanced team.
Examples
input
6
1 10 17 12 15 2
output
3
input
10
1337 1337 1337 1337 1337 1337 1337 1337 1337 1337
output
10
input
6
1 1000 10000 10 100 1000000000
output
1
Note
In the first example you can create a team with skills [12,17,15].
In the second example you can take all students in a team because their programming skills are equal.
In the third example you can create a team consisting of a single student (and you cannot create a team consisting of at least two students).
解题思路
官方：Let's sort all values in non-decreasing order. Then we can use two pointers to calculate for each student
