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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 Jumo {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);


        int j = s.nextInt();
        String n = s.next();

        int max = 0;
        int tmp = 0;


       for (int l = 0; l <= j-5; l++){
        for (int m = 0; m <= j/4 + j%4; m++) {
           max = m;
            for (int i = l; i < j - max - 1; i++) {
                if (n.charAt(i) == '*' && n.charAt(i + max + 1) == '*') {
                    i = i + max;
                    tmp++;
                    if (tmp == 4) {
                        System.out.println("yes");
                        System.exit(0);
                    }
                } else
                    tmp = 0;
            }
            tmp = 0;
        }
           tmp = 0;
        }
            System.out.println("no");
    }
}
