using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using System.Globalization;
using System.Diagnostics;

class Program
{
    public Program() { }
    public static int Main()
    {
        new Program().calc();
        return 0;
    }
    Scanner cin;

    void calc()
    {
        cin = new Scanner();
        int N = cin.nextInt();
        int[] A = cin.ArrayInt(N);

        long ans = 0;
        long cnt = 1;

        for (long i = 0; i <= N; i++)
        {
            if (i != 0 && i != N)
            {
                if (A[i] == A[i - 1])
                {
                    cnt++;
                }
                else
                {
                    ans += cnt / 2;
                    cnt = 1;

                }
            }
            else if (i == N)
            {
                ans += cnt / 2;
            }

        }
        Console.WriteLine(ans);
    }

    long mod = 998244353;
    long powmod(long a, long p)
    {
        long ans = 1;
        long mul = a;
        for (; p > 0; p >>= 1, mul = (mul * mul) % mod)
        {
            if ((p & 1) == 1) ans = (ans * mul) % mod;
        }
        return ans;
    }


    long[] fact; //階乗
    long[] revFact; //階乗の逆元
    void setFact(int N)
    {
        fact = new long[N];
        revFact = new long[N];
        fact[0] = 1;
        for (int i = 1; i < N; i++)
        {
            fact[i] = fact[i - 1] * i;
            fact[i] %= mod;
        }
        revFact[N - 1] = powmod(fact[N - 1], mod - 2);
        for (int i = N - 2; i >= 0; i--)
        {
            revFact[i] = revFact[i + 1] * (i + 1);
            revFact[i] %= mod;
        }
    }


    long getC(int a, int b)
    {
        return (((fact[a] * revFact[b]) % mod) * revFact[a - b]) % mod;
    }

}






class Scanner
{
    string[] s;
    int i;

    char[] cs = new char[] { ' ' };

    public Scanner()
    {
        s = new string[0];
        i = 0;
    }

    public string next()
    {
        if (i < s.Length) return s[i++];
        string st = Console.ReadLine();
        while (st == "") st = Console.ReadLine();
        s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
        if (s.Length == 0) return next();
        i = 0;
        return s[i++];
    }

    public int nextInt()
    {
        return int.Parse(next());
    }
    public int[] ArrayInt(int N, int add = 0)
    {
        int[] Array = new int[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextInt() + add;
        }
        return Array;
    }

    public long nextLong()
    {
        return long.Parse(next());
    }

    public long[] ArrayLong(int N, long add = 0)
    {
        long[] Array = new long[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextLong() + add;
        }
        return Array;
    }

    public double nextDouble()
    {
        return double.Parse(next());
    }


    public double[] ArrayDouble(int N, double add = 0)
    {
        double[] Array = new double[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextDouble() + add;
        }
        return Array;
    }
}


Measured memory_bytes: 11092