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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.InputStreamReader;

public class Solution {

    public static void main(String[] args) throws IOException {
        boolean good = false;
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        int noSegments = Integer.parseInt(br.readLine());

        char[] segments  = br.readLine().toCharArray();

        for(int i = 0; i < noSegments; i++) {
            int j = 1;
            if (segments[i] == '*') {
                while (i + (j * 4) < noSegments) {

                    if (segments[i] == segments[i + j] &&
                            segments[i] == segments[i + (2*j)] &&
                            segments[i] == segments[i + (3 * j)] &&
                            segments[i] == segments[i + (4 * j)]) {

                        good = true;
                        break;
                    }
                    j++;
                }
            }

            if(good) {
                System.out.println("yes");
                break;
            }
        }

        if(!good) {
            System.out.println("no");
        }


    }
}
