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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 Quest_1 {
    public static void main(String args[])
    {
        Scanner input=new Scanner(System.in);
        int n=input.nextInt();
        input.nextLine();
        String level=input.nextLine();
        if(check(level,n))
            System.out.println("yes");
        else
            System.out.println("no");
    }
    public static boolean check(String level,int n)
    {
        for(int i=0;i<=n-5;i++)
        {
            if(level.charAt(i)=='*')
            {
                for(int k=1;k<=((n-1-i)/4);k++)
                {
                    if(level.charAt(i)==level.charAt(i+k) && level.charAt(i)==level.charAt(i+2*k)&& level.charAt(i)==level.charAt(i+3*k)&& level.charAt(i)==level.charAt(i+4*k))
                    {
                        return true;
                    }
                }   
            }
            
        }
        return false;
    }

}
