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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.awt.Point;
import java.util.Arrays;
import java.util.Scanner;

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
/**
 *
 * @author btx
 */
public class a {

    static boolean[] p;

    public static void main(String[] args) {
	Scanner in = new Scanner(System.in);
	int h = in.nextInt();
	String s = in.next();
	if (h > 4) {
	    p = new boolean[h];
	    for (int i = 0; i < h; i++) {
		if (s.charAt(i) == '*') {
		    p[i] = true;
		}
	    }

	    int x = 0;

	    do {
		x++;
		x = Math.max(1, x);
		kovip:
		for (int ip = 0; ip < h; ip++) {
//		    if (5 * x + ip < h) {
//			continue kovip;
//		    }
		    for (int l = 0; l <= 4; l++) {
			if (l * x + ip >= h) {
			    continue kovip;
			}
			if (!p[l * x + ip]) {
			    continue kovip;
			}
			if (l == 4) {
			    System.out.println("yes");
			    return;
			}
		    }
		}
	    } while (h / x >= 4);
	}
	System.out.println("no");

    }

}
