20
.*..*...*....*.....*
 97
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 5
*.***
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 72
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 89
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 100
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 53
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 10
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 69
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 51
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 67
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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.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Scanner;

public class TestAC {

	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int aa = input.nextInt();
		String k = input.next();
		ArrayList<Integer> list1 = new ArrayList<Integer>();
		ArrayList<Integer> list2 = new ArrayList<Integer>();

		for (int i = 0; i < k.length(); i++) {
			if (k.charAt(i) == '*')
				list1.add((i + 1));
		}
		for (int i = 0; i < list1.size(); i++) {
			for (int ii = i + 1; ii < list1.size(); ii++) {
				int sub = Math.abs(list1.get(i) - list1.get(ii));
				list2.add(sub);
			}
		}
		Collections.sort(list2);
		 
		for (int i = 0; i < list2.size(); i++) {
			int fre = Collections.frequency(list2, list2.get(i));
			if (fre >= 5) {
				System.out.println("yes");
				return;
			}
		}
		System.out.println("no");
	}
}
