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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 JavaApplication2 {

	static char[] level;

	public static boolean check(int start, int step) {
		int count = 0;
		for (int i = start; i < level.length; i += step) {
			if (level[i] == '.') {
				return false;
			} else {
				count++;
				if (count == 5) {
					return true;
				}
			}
		}
		return false;
	}

	/**
	 * @param args the command line arguments
	 */
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		level = in.next().toCharArray();
		for (int step = 1; step <= level.length / 4.0; step++) {
			int maxStart = level.length - step * 4;
			for (int start = 0; start <= maxStart; start++) {
				if (check(start, step)) {
					System.out.print("yes");
					return;

				}
			}
		}
		System.out.print("no");
	}

}