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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.awt.*;
import java.io.*;
import java.util.*;
import java.math.BigInteger;
import static java.math.BigInteger.*;
import static java.lang.Math.*;
import static java.util.Arrays.*;

//<editor-fold defaultstate="collapsed" desc="Main">
public class Main {
    // https://netbeans.org/kb/73/java/editor-codereference_ru.html#display

    private void run() {
        try {
            Locale.setDefault(Locale.US);
        } catch (Exception e) {
        }
        boolean oj = true;
        try {
            oj = System.getProperty("MYLOCAL") == null;
        } catch (Exception e) {
        }

        if (oj) {
            sc = new FastScanner(new InputStreamReader(System.in));
            out = new PrintWriter(new OutputStreamWriter(System.out));
//            try {
//                sc = new FastScanner(new FileReader ("stacks.in" ));
//                out = new PrintWriter(new FileWriter("stacks.out"));
//            } catch (IOException e) {
//                MLE();
//            }
        } else {
            try {
                sc = new FastScanner(new FileReader("input.txt"));
                out = new PrintWriter(new FileWriter("output.txt"));
            } catch (IOException e) {
                MLE();
            }
        }
        Solver s = new Solver();
        s.sc = sc;
        s.out = out;
        s.solve();
        if (!oj) {
            err.println("Time: " + (System.currentTimeMillis() - timeBegin) / 1e3);
            err.printf("Mem: %d\n", (Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory()) >> 20);
        }
        out.flush();
    }

    private void show(int[] arr) {
        for (int v : arr) {
            err.print(" " + v);
        }
        err.println();
    }

    public static void exit() {
        err.println("Time: " + (System.currentTimeMillis() - timeBegin) / 1e3);
        err.printf("Mem: %d\n", (Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory()) >> 20);
        out.flush();
        out.close();
        System.exit(0);
    }

    public static void MLE() {
        int[][] arr = new int[1024 * 1024][];
        for (int i = 0; i < arr.length; i++) {
            arr[i] = new int[1024 * 1024];
        }
    }

    public static void main(String[] args) {
        new Main().run();
    }

    static long timeBegin = System.currentTimeMillis();
    static FastScanner sc;
    static PrintWriter out;
    static PrintStream err = System.err;
}
    //</editor-fold>

//<editor-fold defaultstate="collapsed" desc="FastScanner">
class FastScanner {

    BufferedReader br;
    StringTokenizer st;

    FastScanner(InputStreamReader reader) {
        br = new BufferedReader(reader);
        st = new StringTokenizer("");
    }

    String next() {
        while (!st.hasMoreElements()) {
            try {
                st = new StringTokenizer(br.readLine());
            } catch (Exception ex) {
                return null;
            }
        }
        return st.nextToken();
    }

    int nextInt() {
        return Integer.parseInt(next());
    }

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

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

    String nextLine() {
        try {
            return br.readLine();
        } catch (IOException ex) {
            return null;
        }
    }
}
//</editor-fold>

class Solver {

    void aser(boolean OK) {
        if (!OK) {
            Main.MLE();
            //for(;;);
        }
    }

    FastScanner sc;
    PrintWriter out;
    static PrintStream err = System.err;


    void solve(){
        int n;
        String s;

        n = sc.nextInt();
        s = sc.next();

        int a = 0;

        for (int i = 0; i < s.length(); ++i)
        {
            if (s.charAt(i) == '*')
            {
                for(int j = 1; j < s.length(); ++j)
                {
                    boolean ok = true;
                    for (int k = 1; k <= 4; ++k)
                    {
                        if (i + j * k < s.length()&& s.charAt(i + j * k) == '*')
                        {
                            ;
                        }
                        else
                        {
                            ok = false;
                            break;
                        }
                    }
                    if (ok == true)
                    {
                        out.println("yes");
                        return ;
                    }
                }
            }
        }
        out.println("no");
    }
}