using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using static System.Math;

namespace _20190420
{
    class Program
    {
        public static void Main(string[] args)
        {
            using (var sc = new SetConsole())
            {
                int n = GetString().ToInt();
                var str = GetString();
                int count = 0;
                var flg = false;
                var prev = -1;
                for (int i = 0; i < n; i++)
                {
                    
                }
                int charge = 0;
                for (int i = 0; i < n - 1; i++)
                {
                    if (str[i] == '#' && str[i + 1] == '#')
                    {
                        charge++;
                    }
                    else if (str[i] == '#' && str[i + 1] == '.')
                    {
                        count = charge != 0 ? charge : 1;
                        if (flg && prev == i - 1)
                        {
                            count--;
                            flg = false;
                        }
                        else
                        {
                            flg = true;
                        }
                        prev = i + 1;
                    }
                    else
                    {
                        charge = 0;
                    }
                }
                CWrite(count);
            }
        }

        static void CWrite<T>(T str) => Console.WriteLine(str);
        static string GetString() => Console.ReadLine();
        static T[] GetArray<T>()
        {
            var t = typeof(T);
            var str = Console.ReadLine();
            if (t == typeof(string))
            {
                return (T[])(object)str.Split();
            }
            if (t == typeof(int))
            {
                return (T[])(object)str.ToNumArray<T>();
            }
            if (t == typeof(long))
            {
                return (T[])(object)str.ToNumArray<T>();
            }
            if (t == typeof(double))
            {
                return (T[])(object)str.ToNumArray<T>();
            }
            throw new NotSupportedException($"{t} is not supported.");
        }
    }

    class SetConsole : IDisposable
    {
        readonly StreamWriter sw = new StreamWriter(Console.OpenStandardOutput());
        public SetConsole()
        {
            sw.AutoFlush = false;
            Console.SetOut(sw);
        }
        public void Dispose()
        {
            Console.Out.Flush();
            sw.AutoFlush = true;
            Console.SetOut(sw);
        }
    }
    static class ExtentionsLibrary
    {
        public static T[] ToNumArray<T>(this string str)
        {
            var t = typeof(T);
            if (t == typeof(int))
            {
                return (T[])(object)str.Split().Select(int.Parse).ToArray();
            }
            if (t == typeof(long))
            {
                return (T[])(object)str.Split().Select(long.Parse).ToArray();
            }
            if (t == typeof(double))
            {
                return (T[])(object)str.Split().Select(double.Parse).ToArray();
            }
            throw new NotSupportedException();
        }
        public static int ToInt(this string str) => int.Parse(str);
    }

}
