Problem:
Score : 300 points

Problem Statement

You are given an integer sequence of length N, a_1,a_2,...,a_N.

For each 1≤i≤N, you have three choices: add 1 to a_i, subtract 1 from a_i or do nothing.

After these operations, you select an integer X and count the number of i such that a_i=X.

Maximize this count by making optimal choices.

Constraints

1≤N≤10^5

0≤a_i<10^5 (1≤i≤N)

a_i is an integer.

Input

The input is given from Standard Input in the following format:

N
a_1 a_2 .. a_N

Output

Print the maximum possible number of i such that a_i=X.

Sample Input 1

7
3 1 4 1 5 9 2

Sample Output 1

4

For example, turn the sequence into 2,2,3,2,6,9,2 and select X=2 to obtain 4, the maximum possible count.

Sample Input 2

10
0 1 2 3 4 5 6 7 8 9

Sample Output 2

3

Sample Input 3

1
99999

Sample Output 3

1

Solution in Ruby (2.3.3) (judge verdict: Time Limit Exceeded)

number=gets.to_i



array=gets.split

array=array.map(&:to_i)

array2=[]
number.times{
    array2<<0}

i=0
number.times{
    array2[i]=array[i]+1
    
    i=i+1
}

array3=[]
number.times{
    array3<<0}

i=0
number.times{
    array3[i]=array[i]-1
    
    i=i+1
}
array4=array2.sort.reverse
max=array4[0]


x=0
aa=0
max.times{
    timess=array.count(x)+array2.count(x)+array3.count(x)
    if timess>aa
        aa=timess
    
end
       x=x+1 
}

puts aa