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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.io.BufferedReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.IOException;
import java.util.StringTokenizer;
import java.io.InputStream;
import java.io.InputStreamReader;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Igor Kraskevich
 */
public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		FastScanner in = new FastScanner(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskA solver = new TaskA();
		solver.solve(1, in, out);
		out.close();
	}
}

class TaskA {
    public void solve(int testNumber, FastScanner in, PrintWriter out) {
        int n = in.nextInt();
        String s = in.next();
        boolean ok = false;
        for (int pos = 0; pos < n; pos++)
            for (int len = 1; len <= n; len++) {
                boolean cur = true;
                for (int i = 0; i <= 4; i++)
                    if (pos + i * len >= n || s.charAt(pos + i * len) != '*')
                        cur = false;
                ok |= cur;
            }
        out.println(ok ? "yes" : "no");
    }
}

class FastScanner {
    private StringTokenizer tokenizer;
    private BufferedReader reader;

    public FastScanner(InputStream inputStream) {
        reader = new BufferedReader(new InputStreamReader(inputStream));
    }

    public String next() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            String line = null;
            try {
                line = reader.readLine();
            } catch (IOException e) {
                // ignore
            }
            if (line == null)
                return null;
            tokenizer = new StringTokenizer(line);
        }
        return tokenizer.nextToken();
    }

    public int nextInt() {
        return Integer.parseInt(next());
    }

}

