#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, current_count = 0, max_count = 1;
    cin >> n;
    vector<int> a(n);
    for(int a_i = 0;a_i < n;a_i++){
       cin >> a[a_i];
    }
    
    for (int b_i = 0; b_i < n; b_i++) {
        // Go through and find the total max_num if you look at all numbers that are one above the current index
        for (int c_i = 0; c_i < n; c_i++) {
            if ((a[b_i] - a[c_i] == 1) || (a[b_i] - a[c_i] == 0)) { // a number minus itself = 0, which adds 1
                current_count++;
            }
        }
        // Once for loop has run, update max_count if current count is higher than max
        if (current_count > max_count) {
            max_count = current_count;
        }
        current_count = 0;
    }
    cout << max_count;
    return 0;
}