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

public class GoodJumps {

    public static void main(String[] args) {
        InputReader in = new InputReader(System.in);
        int n = in.nextInt();
        String st = in.next();
        for (int i = 0; i < n; i++) {
            if (st.charAt(i) == '.') {
                continue;
            }
            if (isGood(st, i)) {
                System.out.println("yes");
                return;
            }
        }
        System.out.println("no");
    }

    private static boolean isGood(String st, int start) {
        for (int d = 1; d < st.length(); d++) {
            boolean good = true;
            for (int i = start; i < start + 5 * d; i += d) {
                if (i >= st.length() || st.charAt(i) == '.') {
                    good = false;
                    break;
                }
            }
            if (good) {
                return true;
            }
        }
        return false;
    }

    public static class InputReader {
        public BufferedReader reader;
        public StringTokenizer tokenizer;

        public InputReader(InputStream stream) {
            reader = new BufferedReader(new InputStreamReader(stream), 32768);
            tokenizer = null;
        }

        public String next() {
            while (tokenizer == null || !tokenizer.hasMoreTokens()) {
                try {
                    tokenizer = new StringTokenizer(reader.readLine());
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }

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

    }
}
