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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
//package a;

import java.util.Scanner;

/**
 * 
 * @author HASHIM
 *
 */
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String str = "";
		if (n < 1 || n > 100)
			return;
		str = sc.next();
		if (str.length() != n)
			return;
		char c[] = str.toCharArray();
		String ss[] = str.split("\\*");
		int length = 0;
		for (int i = 0; i < ss.length; i++) {

			if (ss[i].length() > length) {
				length = ss[i].length();
			}
		}
		int count = 1;
		for (int i = str.indexOf('*'); i < c.length;) {
			if (i < c.length - length - 1) {
				if (c[i + length + 1] == '*') {
					i = i + length + 1;
					count++;
				} else if (c[i + 1] == '*') {
					i++;
				} else {
					i++;
				}
			} else {
				i++;
			}
		}
		if (count == 5) {
			System.out.println("yes");
		} else {
			System.out.println("no");
		}
	}
}
