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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.util.Scanner;
public class Main {

    public static void main(String[] args) 
    {
        /*53 *.*.****.*.*......**....**.***.*.*.**.*.*.***...*..*.*/
        Scanner s=new Scanner(System.in);
        int n=Integer.parseInt(s.nextLine());
        String str=s.nextLine();
        String o[]=str.split("");
        boolean bool=true;
        int elementos=n;
        int con=0;
        int j=0;
        while(j<n && bool)
        {
            if(o[j].compareTo(".")==0)
            {
                con++;
            }
            else
            {
                bool=false;
            }
            j++;
        }
        elementos-=con;
        con=0;
        j=n-1;
        while(j>=0 && bool)
        {
            if(o[j].compareTo(".")==0)
            {
                con++;
            }
            else
            {
                bool=false;
            }
            j--;
        }
        elementos-=con;
        int saltos=0;
        bool=false;
        for (int i = 0; i < n; i++) 
        {
            if(o[i].compareTo(".")!=0)
            {
                saltos=(elementos-i)/4;
                
                for (int k = 1; k <= saltos; k++) 
                {
                    if(i+(4*k)<n&&o[i+k].compareTo("*")==0 && o[i+(2*k)].compareTo("*")==0&& o[i+(3*k)].compareTo("*")==0&& o[i+(4*k)].compareTo("*")==0 )
                    {
                        System.out.println("yes");
                        i=1000;
                        k+=1000;
                        bool=true;
                    }
                }
            }
        }
        if(!bool)
        {
            System.out.println("no");
        }
    }
}
