#include <iostream>
#include <vector>

int main(void){
  int n;
  std::cin >> n;
  std::vector<int> A(n);

  int last = -1;
  int count = 0;
  std::vector<int> tunagari;
  for(int i=0; i<n; i++){
    std::cin >> A[i];
    if(i){
      if(last != A[i]){
	tunagari.push_back(count);
	count = 0;
      }
    }
    last = A[i];
    count++;
  }
  if(count) tunagari.push_back(count);
  if(tunagari.size()%2) tunagari.push_back(0);

  std::vector<int> dp(tunagari.size()+2);
  for(int i=tunagari.size()-1; i>=0; i--){
    int a = dp[i+2] + tunagari[i];
    int b = dp[i+1];
    dp[i] = a<b?b:a;
  }
  
  std::cout << dp[0] << std::endl;
  
  return 0;
}