using System;
using System.Linq;
using System.Collections.Generic;
using System.Collections;

namespace Algorithm
{
    class Program
    {
        static void Main(string[] args)
        {
            var n = int.Parse(Console.ReadLine());
            var a = Console.ReadLine().Split().Select(int.Parse).ToArray();

            var div = n / 2;
            if (n % 2 == 1) div++;

            var continuous = new List<int>();
            var cur = a[0];
            var count = 1;
            for (var i = 1; i < n; i++)
            {
                if (cur == a[i])
                    count++;
                else
                {
                    continuous.Add(count);
                    count = 1;
                }

                cur = a[i];
            }
            continuous.Add(count);

            var graterOne = false;
            var total = 0;
            var loop = 1;
           foreach (var data in continuous)
            {
                if (data > 1)
                {
                    if (!graterOne && loop != 2) total++;
                    total += data - 1;
                    graterOne = true;
                }
                else
                {
                    if (loop == 1 || (!graterOne && loop == continuous.Count)) total++;
                    graterOne = false;
                }
                loop++;
            }

            Console.WriteLine(Math.Max(div, total));
        }
    }
}