#include <bits/stdc++.h>
using namespace std;
const int MAXN = 2e5;
typedef long long ll;

#define pb push_back
#define mp make_pair

int a[MAXN];
int dp[MAXN][2];
int n;

int main()
{
    cin >> n;
    for(int i = 1; i <= n; ++i)
    {
        cin >> a[i];
    }
    sort(a + 1,a + n + 1);
    int ans = 0;
    for(int i = 1; i <= n; ++i)
    {
        for(int j = i; j <= n; ++j)
        {
            if(a[j] - a[i] <= 1)
            {
                ans = max(ans,j - i + 1);
            }
        }
    }
    cout << ans;
    return 0;
}