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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.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.io.Reader;
import java.util.StringTokenizer;
import java.io.InputStream;

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

class TaskA {
    public void solve(int testNumber, InputReader in, PrintWriter out) {
       
        int n = Integer.parseInt(in.readLine());
        String s = in.readLine();
        int[] a = new int[n];
        for (int i = 0; i < n; i++) {
            if(s.charAt(i) == '*') {
                a[i] = 1;
            }
        }
        for (int i = 0; i < n; i++) {
            if(a[i] == 1) {
                for (int j = 1; j*4+i < n; j++) {
                    if(a[i+j] == 1 && a[i+2*j] == 1 && a[i+3*j] == 1 && a[i+4*j] == 1) {
                        out.print("yes");
                        return;
                    }
                }
            }
        }
        out.print("no");
    }
}

class InputReader  extends BufferedReader {
    public InputReader(InputStream st) {
        super(new InputStreamReader(st));
    }

    public String readLine() {
        try {
            return super.readLine();
        } catch (IOException e) {
            return null;
        }
    }


}
