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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 static java.lang.Double.parseDouble;
import static java.lang.Integer.parseInt;
import static java.lang.Long.parseLong;
import static java.lang.System.exit;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class A {
	
	static BufferedReader in;
	static PrintWriter out;
	static StringTokenizer tok;
	
	static void solve() throws Exception {
		int n = nextInt();
		String s = next();
		for (int i = 0; i < n; i++) {
			if (s.charAt(i) == '.') {
				continue;
			}
			for (int j = i + 1; j < n; j++) {
				if (i + (j - i) * 4 >= n) {
					continue;
				}
				if (s.charAt(j) == '.' ||
					s.charAt(2 * j - i) == '.' ||
					s.charAt(3 * j - 2 * i) == '.' ||
					s.charAt(4 * j - 3 * i) == '.') {
					continue;
				}
				out.print("yes");
				return;
			}
		}
		out.print("no");
	}
	
	static int nextInt() throws IOException {
		return parseInt(next());
	}

	static long nextLong() throws IOException {
		return parseLong(next());
	}

	static double nextDouble() throws IOException {
		return parseDouble(next());
	}

	static String next() throws IOException {
		while (tok == null || !tok.hasMoreTokens()) {
			tok = new StringTokenizer(in.readLine());
		}
		return tok.nextToken();
	}

	public static void main(String[] args) {
		try {
			in = new BufferedReader(new InputStreamReader(System.in));
			out = new PrintWriter(new OutputStreamWriter(System.out));
			solve();
			in.close();
			out.close();
		} catch (Throwable e) {
			e.printStackTrace();
			exit(1);
		}
	}
}
