#include<bits/stdc++.h>
using namespace std;
typedef long long ll;

int main(){
  int N; cin >> N;
  vector<int> A(N);
  for(int i = 0; i < N; i++){ cin >> A[i];}
  
  int head = 0; int tail = 0;
  
  int ans = 0;
  
  vector<bool> flag(N,false);
  
  while( head < N && tail < N){ 
    
    while( A[head] == A[tail]){ tail++;}
    
    if( tail-head >= 2){ 
      for(int i = head; i < tail; i++){ flag[i] = true;}
    }
    
    head = tail;
  }
  
  head = 0; tail = 0;
  int cnt = 0;
  while( head < N && tail < N){
    
    if( flag[head]){
      
      while( flag[tail] && tail < N) { tail++;}
      cnt += tail-head;
      
      head = tail;
    }
    else{
      
      while( !flag[tail] && tail < N){ tail++;}
      
       if( (tail-head)%2){
         if( head == 0 && tail == N){ cnt += (tail-head+1)/2;}
         else{cnt += (tail-head-1)/2;}
       }
      
      else{ 
        if( head == 0 || tail == N){
          cnt += (tail-head)/2;}
        else{ 
          cnt += (tail-head-2)/2;}
      }
      
      head = tail;
    }
  }
 
  cout << cnt << endl; return 0;
}