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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.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;

/**
 * @author: Ashok Rajpurohit
 * problem Link:  http://codeforces.com/contest/526/problem/0
 */

public class Z15A {

    private static PrintWriter out;
    private static InputStream in;

    public static void main(String[] args) throws IOException {
        OutputStream outputStream = System.out;
        in = System.in;
        out = new PrintWriter(outputStream);
        Z15A a = new Z15A();
        a.solve();
        out.close();
    }

    public void solve() throws IOException {
        InputReader in = new InputReader();
        int n = in.readInt();
        String s = in.read();

        for (int i = 0; i < n; i++) {
            for (int j = 1; i + (j << 2) < n; j++) {
                if (s.charAt(i) == '*' && s.charAt(i) == s.charAt(i + j) &&
                    s.charAt(i) == s.charAt(i + j + j) &&
                    s.charAt(i) == s.charAt(i + 3 * j) &&
                    s.charAt(i) == s.charAt(i + 4 * j)) {
                    out.println("yes");
                    return;
                }
            }
        }
        out.println("no");
    }

    final static class InputReader {
        byte[] buffer = new byte[8192];
        int offset = 0;
        int bufferSize = 0;

        public int readInt() throws IOException {
            int number = 0;
            int s = 1;
            if (offset == bufferSize) {
                offset = 0;
                bufferSize = in.read(buffer);
            }
            if (bufferSize == -1)
                throw new IOException("No new bytes");
            for (; buffer[offset] < 0x30 || buffer[offset] == '-'; ++offset) {
                if (buffer[offset] == '-')
                    s = -1;
                if (offset == bufferSize - 1) {
                    offset = -1;
                    bufferSize = in.read(buffer);
                }
            }
            for (; offset < bufferSize && buffer[offset] > 0x2f; ++offset) {
                number = (number << 3) + (number << 1) + buffer[offset] - 0x30;
                if (offset == bufferSize - 1) {
                    offset = -1;
                    bufferSize = in.read(buffer);
                }
            }
            ++offset;
            return number * s;
        }

        public String read() throws IOException {
            StringBuilder sb = new StringBuilder();
            if (offset == bufferSize) {
                offset = 0;
                bufferSize = in.read(buffer);
            }

            if (bufferSize == -1 || bufferSize == 0)
                throw new IOException("No new bytes");

            for (;
                 buffer[offset] == ' ' || buffer[offset] == '\t' || buffer[offset] ==
                 '\n' || buffer[offset] == '\r'; ++offset) {
                if (offset == bufferSize - 1) {
                    offset = -1;
                    bufferSize = in.read(buffer);
                }
            }
            for (; offset < bufferSize; ++offset) {
                if (buffer[offset] == ' ' || buffer[offset] == '\t' ||
                    buffer[offset] == '\n' || buffer[offset] == '\r')
                    break;
                if (Character.isValidCodePoint(buffer[offset])) {
                    sb.appendCodePoint(buffer[offset]);
                }
                if (offset == bufferSize - 1) {
                    offset = -1;
                    bufferSize = in.read(buffer);
                }
            }
            return sb.toString();
        }
    }
}
