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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.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;

public class A {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        PrintWriter out = new PrintWriter(System.out);

        int n = in.nextInt();
        char[] c = in.next().toCharArray();

        out.println(isgood(c) ? "yes" : "no");
        out.flush();
    }

    private static boolean isgood(char[] c) {
        int n = c.length;
        for (int i = 0 ; i < n ; i++) {
            if (c[i] == '*') {
                for (int j = 1; j <= n; j++) {
                    if (dfs(c, j, i, 0)) {
                        return true;
                    }
                }
            }
        }
        return false;
    }

    private static boolean dfs(char[] c, int k, int now, int time) {
        if (now >= c.length || c[now] == '.') {
            return false;
        }
        if (time == 4) {
            return true;
        }
        return dfs(c, k, now+k, time+1);
    }


    static void debug(Object... o) {
        System.err.println(Arrays.deepToString(o));
    }
}


