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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.util.*;


public class King
{
   public static void main(String[] args)
   {
      Scanner in = new Scanner(System.in);
      int n = in.nextInt();
      String s = in.next();
      char[] charray = new char[n];
      for(int i=0;i<n;i++)
         charray[i]=s.charAt(i);
      for(int gap=1;gap<25;gap++)
      {
         for(int start = 0;start<=n;start++)
         {
            int two = start + gap;
            int three = start + gap*2;
            int four = start + gap*3;
            int five = start + gap*4;
            if(five>=n)
               break;
            if(charray[start]=='*' && charray[two]=='*' && charray[three]=='*' && charray[four]=='*' && charray[five]=='*')
            {
               System.out.println("yes");
               System.exit(0);
            }
         }
      }
      System.out.println("no");
   }
}