/* -*- coding: utf-8 -*-
 *
 * 921.cc:  No.921 ずんだアロー - yukicoder
 */

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<iostream>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<stack>
#include<list>
#include<queue>
#include<deque>
#include<algorithm>
#include<numeric>
#include<utility>
#include<complex>
#include<functional>
 
using namespace std;

/* constant */

/* typedef */

/* global variables */

/* subroutines */

/* main */

int main() {
  int n;
  scanf("%d", &n);

  int dp0 = 0, dp1 = 0, pa = 0;
  for (int i = 0; i < n; i++) {
    int ai;
    scanf("%d", &ai);

    int ndp0 = max(dp0, dp1);
    int ndp1 = (pa == ai) ? max(dp0, dp1) + 1 : dp0 + 1;

    dp0 = ndp0, dp1 = ndp1, pa = ai;
  }

  printf("%d\n", max(dp0, dp1));
  return 0;
}