//#define _GLIBCXX_DEBUG
#include "bits/stdc++.h"

using namespace std;

//------------------------------- Libraries --------------------------------//

//------------------------------- Type Names -------------------------------//

using i64 = int_fast64_t;

using seika = string;
//akari : 1D, yukari : 2D, maki : 3D vector
template <class kizuna>
using akari = vector<kizuna>;
template <class yuzuki>
using yukari = akari<akari<yuzuki>>;
template <class tsurumaki>
using maki = akari<yukari<tsurumaki>>;
//akane : ascending order, aoi : decending order
template <class kotonoha>
using akane = priority_queue<kotonoha, akari<kotonoha>, greater<kotonoha>>;
template <class kotonoha>
using aoi = priority_queue<kotonoha>;

//------------------------------- Dubug Functions ---------------------------//
inline void print()
{
    cout << endl;
}
template <typename First, typename... Rest>
void print(const First &first, const Rest &... rest)
{
    cout << first << ' ';
    print(rest...);
}
//------------------------------- Solver ------------------------------------//

void solve()
{
    int n;
    cin >> n;
    akari<int> as(n), dp(2);
    for (int i = 0; i < n; i++)
    {
        cin >> as[i];
    }
    for (int i = 0; i < n; i++)
    {
        akari<int> nx(2);
        if (i)
        {
            nx[1] = max(dp[0] + 1, dp[1] + (as[i] == as[i - 1]));
            nx[0] = max(dp[0], dp[1]);
        }
        else
        {
            nx[1] = 1;
        }
        swap(dp, nx);
    }
    cout << max(dp[0], dp[1]) << endl;
}

int main()
{
    solve();
    return 0;
}