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-----
7
3 1 4 1 5 9 2

-----Sample Output-----
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.

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