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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 ex6 {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        long[] tab = new long[28];
        Scanner input = new Scanner(System.in);
        int length = input.nextInt();

        String thing = input.next();

        boolean r = false;
        int jumped = 0;
        while (!r && thing.length() >= length / 4&&thing.indexOf('*')!=-1){
            for (int jump = 1; jump <= (thing.length() / 4); jump++) {

                

                int i = thing.indexOf('*');
                jumped = 0;
                while (i+jump<thing.length()&&jumped <= 3 && thing.charAt(i + jump) == '*') {
                    // System.out.println();
                    i += jump;
                    jumped++;
                }
                if (jumped > 3) {
                    r = true;
                    break;
                }
            }
        thing=thing.substring(thing.indexOf('*')+1) ;
        
        
        }
        if (r)
            System.out.println("yes");
        else
            System.out.println("no");

    }

}
