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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 java.io.InputStream;
import java.io.FilterInputStream;
import java.util.NoSuchElementException;
import java.io.BufferedInputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Iterator;
import java.io.IOException;

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

class TaskA {
    public void solve(int testNumber, InputUtil in, PrintWriter out) {
        int n = in.nextInt();
        char[] a = in.next().toCharArray();
        for (int i = 0; i < n; i++) {
            if (a[i] == '*') {
                A: for (int j = 1; i + j * 4 < n; j++) {
                    for (int k = 1; k < 5; k++) {
                        if (a[i + j * k] == '.') {
                            continue A;
                        }
                    }
                    out.println("yes");
                    return;
                }
            }
        }
        out.println("no");
}
}

class InputUtil {

    JoltyScanner in;

    public InputUtil(InputStream istream) {
        in = new JoltyScanner(istream);
    }

    public String next() {
        return in.nextOrNull();
    }

    public int nextInt() {
        String s = next();
        if (s == null) {
            throw new NoSuchElementException("Attempted to read integer that is not there.");
        }
        return Integer.parseInt(s);
    }

}

class JoltyScanner {
    public static final int BUFFER_SIZE = 1 << 16;
	public static final char NULL_CHAR = (char) -1;

    BufferedInputStream in;
	StringBuilder str = new StringBuilder();
	byte[] buffer = new byte[BUFFER_SIZE];
	boolean EOF_FLAG = false;

    char c = NULL_CHAR;
	int bufferIdx = 0;
    int size = 0;

	public JoltyScanner(InputStream in) {
		this.in = new BufferedInputStream(in, BUFFER_SIZE);
	}

    public String next() {
		checkEOF();
		for (c = c == NULL_CHAR ? nextChar() : c; Character.isWhitespace(c); checkEOF()) {
			c = nextChar();
		}
		str.setLength(0);
		for (; !EOF_FLAG && !Character.isWhitespace(c); c = nextChar()) {
			str.append(c);
		}
		return str.toString();
	}

	public String nextOrNull() {
		try {
			return next();
		} catch (EndOfFileException e) {
			return null;
		}
	}

    public char nextChar() {
		if (EOF_FLAG) {
			return NULL_CHAR;
		}
		while (bufferIdx == size) {
			try {
				size = in.read(buffer);
				if (size == -1) {
					throw new Exception();
				}
			} catch (Exception e) {
				EOF_FLAG = true;
				return NULL_CHAR;
			}
			if (size == -1) {
				size = BUFFER_SIZE;
			}
			bufferIdx = 0;
		}
		return (char) buffer[bufferIdx++];
	}

    public void checkEOF() {
		if (EOF_FLAG) {
			throw new EndOfFileException();
		}
	}

	public class EndOfFileException extends RuntimeException {
	}
}

