#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int main(){
    int n; 
    int count = 0, count1 = 0, max = 0, max1 = 0;
    scanf("%d",&n);
    int *a = malloc(sizeof(int) * n);
    for(int a_i = 0; a_i < n; a_i++){
        
       scanf("%d",&a[a_i]);
        
    }
    for(int i = 0; i < n; i++){
        count = 0;
        count1 = 0;
         
        for(int j = 0 ; j <= n; j++){
            if(((a[i] - a[j]) <= 1) && ((a[i] - a[j]) >= 0)){
                count++;
                
            }
         if((a[i] - a[j]) < 0 && abs(a[i] - a[j]) <= 1 ){
                count1++;
                
            }   
        }
         if(count > max) max = count;
        if(count1 > max1) max1 = count1;
    }
    if(max >= max1) printf("%d",max);
    else printf("%d",max1);
    return 0;
}