#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];
    }
    int i, j, aa=0, b, k[105] = {0};
    for(i=0;  i<n; i++){
        k[i] = 0;
        for(j=0; j<n; j++){
            if((a[i]-a[j])<=1 and (a[i]-a[j])>=0 )
                k[i]++;
        }
        aa = max(aa, k[i]);
        //cout << aa << " " << k[i] << " " << i << endl;
    }
    for(i=0;  i<n; i++){
        k[i] = 0;
        for(j=0; j<n; j++){
            if((a[j]-a[i])<=1 and (a[j]-a[i])>=0 )
                k[i]++;
        }
        aa = max(aa, k[i]);
        //cout << aa << " " << k[i] << " " << i << endl;
    }
    
    cout << aa << endl;
    return 0;
}