#!/bin/ruby

n = gets.strip.to_i
a = gets.strip
a = a.split(' ').map(&:to_i)
m = 0

a.each do |x|
    temp = 0
    a.each do |y|
        temp += 1 if (1 >= (x - y) && (x - y) >= 0)
    m = temp if (temp > m)
    end
end
a.each do |x|
    temp = 0
    a.each do |y|
    temp += 1 if (-1 <= (x - y) && (x - y) <= 0)
    m = temp if (temp > m)
    end
end
puts m