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 5
****.

no yes no no no yes yes no yes yes yes yes yes yes no yes yes yes yes yes yes yes yes yes yes yes no no no yes yes yes yes no no yes yes yes yes yes no yes yes no no no yes yes no yes yes no no no yes yes yes yes no yes yes yes no
import java.io.*;
import java.util.*;


public class A
{
    public static void main(String [] args) throws IOException
    {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter writer = new PrintWriter(new OutputStreamWriter(System.out));

        int n = Integer.parseInt(reader.readLine());
        char [] map = reader.readLine().toCharArray();

        boolean res = false;
        for(int s = 0 ; s < n ; s++)
            if(map[s] == '*')
                for(int jumpLen = 1 ; jumpLen <= n ; jumpLen++)
                {
                    boolean good = true;
                    for(int k = 1 ; k <= 4 ; k++)
                        if(!(s + k*jumpLen < n && map[s+k*jumpLen] == '*'))
                            good = false;
                    if(good)
                        res = true;
                }

        if(res)
            writer.println("yes");
        else
            writer.println("no");

        writer.flush();
        writer.close();
    }
}