#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#include <algorithm>
#include <queue>
#include <string>
#include <cmath>
#include <map>
#include <set>
#include <cassert>
#define MOD 1e9 + 7
#define eps 1e-9
#define pb push_back
#define mp make_pair
#define ft first
#define sd second
#define sz(a) a.size()
#define loop(i, n) for(long long (i) = 0; (i) < (n) ; ++ (i))
#define loopn()
#define pii pair<int,int>
#define pll pair<long long,long long>
#define vii vector<int>
#define vll vector<long long>  
typedef long long ll;
typedef long double ld;
 
using namespace std;
 
/*@Sergey_Miller*/
void solve() {
    ll n;
    cin >> n;
    vll a(n);
    loop(i,n) {
        cin >> a[i];
    }
    vll b(n,0);
    loop(i,n) {
        loop(j,n) {
            if(a[i]-a[j] <= 1 && a[i] - a[j] >= 0) {
                ++b[i];
            }
        }
    }
    ll maxx = 0;
    loop(i,n) {
        maxx = max(maxx, b[i]);
    }
    cout << maxx << endl;
}
 
int main () {
    ios::sync_with_stdio(false);
    // freopen("input.txt", "r", stdin);
 //  freopen("output.txt", "w", stdout);
    solve();
    // cout << 10000000320 % 1000000033;
    // cout << 92381%17;
    return 0;
}