#include <bits/stdc++.h>
using namespace std;
#define int long long
using ll = long long;
#define REP(i,n) for(int i = 0;i < (int)(n);i++)
#define RREP(i,n) for(int i = (int)n-1;i >= 0;i--)
#define FOR(i,s,n) for(int i = s;i < (int)n;i++)
#define RFOR(i,s,n) for(int i = (int)n-1;i >= s;i--)
#define ALL(a) a.begin(),a.end()
#define IN(a, x, b) (a<=x && x<b)
template<class T>inline bool CHMAX(T&a,T b){if(a<b){a = b;return true;}return false;}
template<class T>inline bool CHMIN(T&a,T b){if(a>b){a = b;return true;}return false;}
constexpr long long INF = 1e18, MOD = 1000000007;

int dp[200020][2];

signed main(){
	int N;
	cin>>N;
	vector<int>a(N);
	REP(i,N){
		cin>>a[i];
	}
	REP(i,200020)REP(j,2)dp[i][j]=-1;
	dp[0][0] = 0;
	dp[0][1] = 1;
	FOR(i,0,N-1){
		if(a[i+1]==a[i]){
			CHMAX(dp[i+1][1],dp[i][1]+1);
			CHMAX(dp[i+1][0],dp[i][0]);
			CHMAX(dp[i+1][1],dp[i][0]+1);
		}else{
			CHMAX(dp[i+1][1],dp[i][0]+1);
			CHMAX(dp[i+1][0],dp[i][1]);
		}
	}
	cout<<max(dp[N-1][0],dp[N-1][1])<<endl;
}