#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define all(c) c.begin(),c.end()
#define pb push_back
#define fs first
#define sc second
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
using namespace std;
template<class S,class T> ostream& operator<<(ostream& o,const pair<S,T> &p){
	return o<<"("<<p.fs<<","<<p.sc<<")";
}
template<class T> ostream& operator<<(ostream& o,const vector<T> &vc){
	o<<"{";
	for(const T& v:vc) o<<v<<",";
	o<<"}";
	return o;
}
using ll = long long;
template<class T> using V = vector<T>;
template<class T> using VV = vector<vector<T>>;
constexpr ll TEN(int n) { return (n == 0) ? 1 : 10 * TEN(n-1); }

#ifdef LOCAL
#define show(x) cerr << "LINE" << __LINE__ << " : " << #x << " = " << (x) << endl
#else
#define show(x) true
#endif
int main(){
	int N;cin >> N;
	using P = pair<int,int>;
	V<P> v;
	rep(i,N){
		int x; cin >> x;
		if(v.empty() || v.back().fs != x) v.pb(P(x,1));
		else v.back().sc++;
	}
	int K = v.size();
	int a = 0,b = 0;
	rep(i,K){
		int x = v[i].sc;
		int na = b + x;
		int nb = max(a,b);
		a=na,b=nb;
	}
	cout << max(a,b) << endl;
}