#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);
    for(int a_i = 0;a_i < n;a_i++){
       cin >> a[a_i];
    }
    sort(a.begin(), a.end());
    
    int j = 0;
    int q = 0;
    int Q = 0;
    for (int i = 0; i < n; i++)
    {
        if (a[i] - a[j] > 1)
        {
            q = 1;
            j = i;            
        }
        else
            q++;
        if (q > Q)
            Q = q;        
    }
    
    cout << Q << endl;
    
    return 0;
}