import java.util.ArrayList;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            a[i] = sc.nextInt();
        }

        ArrayList<Integer> list = new ArrayList<>();
        int prev = a[0];
        int count = 0;
        for (int i : a) {
            if (i == prev) {
                count++;
            } else {
                list.add(count);
                count = 1;
                prev = i;
            }
        }
        list.add(count);
        list.add(0);
        list.add(0);
        list.add(0);

//        for (int i = 0; i < list.size(); i++) {
//            System.out.print(list.get(i)+" ");
//        }
//        System.out.println();

        int ans = 0;

        for (int i = 0; i < list.size() - 3; i++) {
            if (list.get(i) - list.get(i + 1) >= list.get(i + 1) - list.get(i) - list.get(i + 2)) {
                ans += list.get(i);
                i++;
            } else {
                ans += list.get(i + 1);
                i+=2;
            }
        }

        System.out.println(ans);
    }
}