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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.*;
import java.util.*;
import java.math.*;


public class Main implements Runnable {
    static BufferedReader in;
    static PrintWriter out;
    static StringTokenizer tok;
    
    
    static void solve() throws Exception {
        int n = nextInt();
        String s = next();
        for (int len = 1; len <= n; ++len) {
            for (int i = 0; i < n; ++i) {
                if (s.charAt(i) == '*') {
                    boolean ok = true;
                    for (int j = 1; j <= 4; ++j) {
                        if (i + len * j >= n || s.charAt(i + len * j) == '.') {
                            ok = false;
                            break;
                        }
                    }
                    if (ok) {
                        out.println("yes");
                        return;
                    }
                }
            }
        }
        out.println("no");
    }
    
    static int nextInt() throws IOException {
        return Integer.parseInt(next());
    }

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

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

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

    static boolean hasNext() throws IOException {
        while (tok == null || !tok.hasMoreTokens()) {
            String s = in.readLine();
            if (s == null) {
                return false;
            }
            tok = new StringTokenizer(s);
        }
        return true;
    }
    
    public static void main(String args[]) {
        new Thread(null, new Main(), "Main", 1 << 28).start();
    }
    
    public void run() {
        try {
            in = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(new OutputStreamWriter(System.out));
            //in = new BufferedReader(new FileReader("input.in"));
            //out = new PrintWriter(new FileWriter("output.out"));
            Locale.setDefault(Locale.US);
            solve();
            in.close();
            out.close();
        } catch (Throwable e) {
            e.printStackTrace();
            java.lang.System.exit(1);
        }
    }
}