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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 Main {
   public static void main(String...args){
       int n;
       Scanner scanner = new Scanner(System.in);
       n = scanner.nextInt();
       String s = scanner.next();
       char [] a = s.toCharArray();
       int start = -1;
       int pit = 0;
       for(int i = 0; i < n; i++)
       {
           if(a[i] == '*'&&start == -1)
               start = i+1;
           if(start!=-1&&a[i]=='.')
           {
               pit = i;
               break;
           }
       }
       int nextStart = -1;
       for(int i = pit; i < n; i++)
       {
           if(a[i] == '*')
           {
               nextStart = i+1;
               break;
           }
       }
       int distance = nextStart-start;
       boolean result = true;
       for(int i = start-1; i < n; i+=distance)
       {
           if(a[i]=='.')
           {
               result = false;
               break;
           }

       }
       if(result == true&&start != -1)
           System.out.println("yes") ;
       else
           System.out.println("no");

   }
}

  	  	  								   	  	  			 		