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****.

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 Main {
    public static void main(String[] args) throws Exception {
        Reader.init(System.in);
        int n = Reader.nextInt() ; 
        char [] c = Reader.next().toCharArray() ;  
        for (int i=0 ; i<=c.length-5 ; i++)
        {
            if (c[i]=='*')
            {
                for (int j=1 ; (j*4)+i<c.length ; j++)           
                {             
                    if (c[i+j]=='*'&&c[i+(j*2)]=='*'&&c[i+(j*3)]=='*'&&c[i+(j*4)]=='*')
                    {
                        System.out.println("yes");    
                        return ;
                    }                     
                }
            }
        }  
        System.out.println("no");
   
    }
}

class Reader {

    static BufferedReader reader;
    static StringTokenizer tokenizer;

    /**
     * call this method to initialize reader for InputStream
     */
    static void init(InputStream input) {
        reader = new BufferedReader(
                new InputStreamReader(input));
        tokenizer = new StringTokenizer("");
    }

    /**
     * get next word
     */
    static String next() throws IOException {
        while (!tokenizer.hasMoreTokens()) {
            //TODO add check for eof if necessary
            tokenizer = new StringTokenizer(
                    reader.readLine());
        }
        return tokenizer.nextToken();
    }

    static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }

    static byte nextByte() throws IOException {
        return Byte.parseByte(next());
    }

    static long nextLong() throws IOException {
        return Long.parseLong(next());
    }

    static double nextDouble() throws IOException {
        return Double.parseDouble(next());
    }
}