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.

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.

Constraints

• 1≤N≤10^5
• 0≤a_i<10^5 (1≤i≤N)
• a_i is an integer.

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

见题面 Input 部分

见题面 Output 部分