#pragma GCC optimize ("O3")
#pragma GCC target ("avx")
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define rep(i, n) for(int i = 0; i < (n); i++)
#define rep1(i, n) for(int i = 1; i <= (n); i++)
#define co(x) cout << (x) << "\n"
#define cosp(x) cout << (x) << " "
#define ce(x) cerr << (x) << "\n"
#define cesp(x) cerr << (x) << " "
#define pb push_back
#define mp make_pair
#define chmin(x, y) x = min(x, y)
#define chmax(x, y) x = max(x, y)
#define Would
#define you
#define please


int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);


	int N;
	cin >> N;
	int dp0 = 0, dp1 = 1;

	int mae;
	cin >> mae;
	rep(i, N - 1) {
		int a;
		cin >> a;

		if (a == mae) {
			int kari = max(dp0, dp1) + 1;
			dp0 = max(dp0, dp1);
			dp1 = kari;
		}
		else {
			int kari = dp0 + 1;
			dp0 = max(dp0, dp1);
			dp1 = kari;
		}
		mae = a;
	}

	co(max(dp0, dp1));


	Would you please return 0;
}