#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <string>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <climits>
#include <cstring>
#include <cstdlib>
#include <fstream>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <unordered_map>

using namespace std;


int main(){
    int n;
    cin >> n;
    vector<int> a(n);
    
    int left_index;
    left_index = 0;

    int aux, count;
    count = 1;
    aux = 1;
    for(int a_i = 0;a_i < n;a_i++){
        cin >> a[a_i];
    }
    
    sort(a.begin(),a.end());

    for(int a_i = 0;a_i < n;a_i++){
        //cout << "Checando " << a[a_i];
        if (abs(a[a_i] - a[left_index]) <= 1) {
            if (left_index != a_i) {
                aux++;
                //cout << "... contou \n";
            }
                
           // cout << " \n";
        } else {
            
            //cout << "zerou\n";
            if (aux > count) 
                count = aux;
            
            int i = 0;
            aux += 1;
            while (a[left_index+i] - a[left_index] == 0) {
                i++;
                aux--;
            }

            left_index += i;
            //cout << "Próximo left: " << left_index << ", currAux: " << aux <<"\n";
            
        }
    }
    
    if (aux > count) {
        count = aux;
    }
    
    cout << count;
    
    return 0;
}