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 5
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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.io.*;
import java.util.*;

public class A {

    void solve() throws IOException {
        in = new InputReader("__std");
        out = new OutputWriter("__std");

        int n = in.readInt();
        char[] s = in.readToken().toCharArray();
        boolean flag = false;
        for (int l = 1; l < n && !flag; ++l) {
            for (int p = 0; p < n && !flag; ++p) {
                flag = true;
                for (int k = 0; k < 5 && flag; ++k) {
                    int i = p + l * k;
                    flag = i < n && s[i] == '*';
                }
            }
        }
        out.println(flag ? "yes" : "no");

        exit();
    }

    void exit() {
        //System.err.println((System.currentTimeMillis() - startTime) + " ms");
        out.close();
        System.exit(0);
    }

    InputReader in;
    OutputWriter out;

    //long startTime = System.currentTimeMillis();

    public static void main(String[] args) throws IOException {
        new A().solve();
    }

    class InputReader {

        private InputStream stream;

        private byte[] buffer = new byte[1024];
        private int pos, len;

        private int cur;

        private StringBuilder sb = new StringBuilder(32);

        InputReader(String name) throws IOException {
            if (name.equals("__std")) {
                stream = System.in;
            } else {
                stream = new FileInputStream(name);
            }
            cur = read();
        }

        private int read() throws IOException {
            if (len == -1) {
                throw new EOFException();
            }
            if (pos >= len) {
                pos = 0;
                len = stream.read(buffer);
                if (len == -1) return -1;
            }
            return buffer[pos++];
        }

        char readChar() throws IOException {
            if (cur == -1) {
                throw new EOFException();
            }
            char res = (char) cur;
            cur = read();
            return res;
        }

        int readInt() throws IOException {
            if (cur == -1) {
                throw new EOFException();
            }
            while (whitespace()) {
                cur = read();
            }
            if (cur == -1) {
                throw new EOFException();
            }
            int sign = 1;
            if (cur == '-') {
                sign = -1;
                cur = read();
            }
            int res = 0;
            while (!whitespace()) {
                if (cur < '0' || cur > '9') {
                    throw new NumberFormatException();
                }
                res *= 10;
                res += cur - '0';
                cur = read();
            }
            return res * sign;
        }

        long readLong() throws IOException {
            if (cur == -1) {
                throw new EOFException();
            }
            return Long.parseLong(readToken());
        }

        double readDouble() throws IOException {
            if (cur == -1) {
                throw new EOFException();
            }
            return Double.parseDouble(readToken());
        }

        String readLine() throws IOException {
            if (cur == -1) {
                throw new EOFException();
            }
            sb.setLength(0);
            while (cur != -1 && cur != '\r' && cur != '\n') {
                sb.append((char) cur);
                cur = read();
            }
            if (cur == '\r') {
                cur = read();
            }
            if (cur == '\n') {
                cur = read();
            }
            return sb.toString();
        }

        String readToken() throws IOException {
            if (cur == -1) {
                throw new EOFException();
            }
            while (whitespace()) {
                cur = read();
            }
            if (cur == -1) {
                throw new EOFException();
            }
            sb.setLength(0);
            while (!whitespace()) {
                sb.append((char) cur);
                cur = read();
            }
            return sb.toString();
        }

        boolean whitespace() {
            return cur == ' ' || cur == '\t' || cur == '\r' || cur == '\n' || cur == -1;
        }

        boolean eof() {
            return cur == -1;
        }
    }

    class OutputWriter {

        private PrintWriter writer;

        OutputWriter(String name) throws IOException {
            if (name.equals("__std")) {
                writer = new PrintWriter(System.out);
            } else {
                writer = new PrintWriter(name);
            }
        }

        void print(String format, Object ... args) {
            writer.print(new Formatter(Locale.US).format(format, args));
        }

        void println(String format, Object ... args) {
            writer.println(new Formatter(Locale.US).format(format, args));
        }

        void print(Object value) {
            writer.print(value);
        }

        void println(Object value) {
            writer.println(value);
        }

        void println() {
            writer.println();
        }

        void close() {
            writer.close();
        }
    }
}
