import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {
    public static int solve(int[] a, int start){
        if(a==null || a.length==1){
            return 1;
        }
        int first = a[start];
        int count1 = 0;
        int count2 = 0;
        for(int i=0;i< a.length;i++){
            if (a[i]<= (first+1)&& a[i]>= first){
                count1++;
            }
            if(a[i]>=(first-1)&& a[i]<= first){
                count2++;
            }
            
        }
        return Math.max(count1, count2);
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] a = new int[n];
        for(int a_i=0; a_i < n; a_i++){
            a[a_i] = in.nextInt();
        }
        int max = 1;
        for(int i=0;i<a.length;i++){
            //System.out.println("here:"+ solve(a, i));
            if(solve(a,i)>max){
                max = solve(a,i);
            }
        }
        System.out.println(max);
    }
}