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 99
***************************************************************************************************
 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.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		String str = scan.next();
		int c1 = 0;
		int c2 = 0;
		int a1[] = new int[110];
		int b1[] = new int[110];
		int map1[] = new int[610];
		int map2[] = new int[610];
		for (int i = 0; i < str.length(); i++) {
			if (str.charAt(i) == '*') {
				a1[c1++] = i;
				map1[i] = 1;
			} else {
				b1[c2++] = i;
				map2[i] = 1;
			}
		}

		if (n < 5) {
			System.out.println("no");
			
		}
	
		else{
		int j = 0;
		int flag1 = 0;
		
		int cha = 0;
		for1: for (int i = 0; i <= c1 - 5; i++) {
			for (cha = a1[j] - a1[i]; cha <= a1[c1 - 5] - a1[i]; j++) {
				if (map1[a1[i]] == 1 && map1[a1[i] + cha] == 1
						&& map1[a1[i] + 2 * cha] == 1
						&& map1[a1[i] + 3 * cha] == 1
						&& map1[a1[i] + 4 * cha] == 1) {
					flag1 = 1;
					break for1;
				}
				cha = a1[j] - a1[i];
			}

		}

	
		if ((flag1) == 1) {
			System.out.println("yes");
		} else {
			System.out.println("no");
		}
		}
	}
}
