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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.InputStreamReader;
import java.io.PrintWriter;

public class CR2015A {
    static int n;

    public static void main(String[] args) throws Exception {
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter pw = new PrintWriter(System.out);
        n = Integer.parseInt(r.readLine());
        char[] cc = r.readLine().trim().toCharArray();
        String result = "no";
        for (int start = 0; start < n; start++) {
            for (int delta = 1; delta <= 35; delta++) {
                boolean isGood = true;
                for (int i = 0; i < 5; i++) {
                    int position = start + i * delta;
                    if (position >= n || cc[position] == '.') {
                        isGood = false;
                    }
                }
                if (isGood) {
                    result = "yes";
                }
            }
        }
        pw.println(result);
        pw.flush();
    }
}
