#!/bin/python

import sys


n = int(raw_input().strip())
a = map(int,raw_input().strip().split(' '))
def close(arr, d):
    p, n = 0, 0
    for a in arr:
        if abs(a-d)<=1:
            if a > d:
                p += 1
            elif a < d:
                n += 1
            else:
                n += 1
                p += 1
                
    return max(p, n)


print max(close(a, k) for k in a)