#include <bits/stdc++.h>
using namespace std;
template<typename T1,typename T2> inline void chmin(T1 &a,T2 b){if(a>b) a=b;}
template<typename T1,typename T2> inline void chmax(T1 &a,T2 b){if(a<b) a=b;}
using Int = long long;
const char newl = '\n';

//INSERT ABOVE HERE
signed main(){
  cin.tie(0);
  ios::sync_with_stdio(0);

  int n;
  cin>>n;
  vector<int> as(n+1);
  for(int i=1;i<=n;i++) cin>>as[i];

  vector<int> dp0(n+1),dp1(n+1);
  for(int i=1;i<=n;i++){
    chmax(dp0[i],dp0[i-1]);
    chmax(dp0[i],dp1[i-1]);
    chmax(dp1[i],dp0[i-1]+1);
    if(as[i]==as[i-1]) chmax(dp1[i],dp1[i-1]+1);
  }

  cout<<max(dp0[n],dp1[n])<<newl;
  return 0;
}