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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 kingOfThieves {

   public static void main(String[] args) throws IOException {
		// TODO Auto-generated method stub
	BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String str = br.readLine();
		int n = Integer.parseInt(str);

		str = br.readLine();
		int x = 0;
		int cnt = 0;
		for (int i = 0; i < n; i++)
			if (str.charAt(i) == '*')
				cnt++;

		int A[] = new int[cnt];

		for (int i = 0; i < n; i++) {
			if (str.charAt(i) == '*')
				A[x++] = i + 1;
		}

		boolean f = false;

		for (int i = 0; i < cnt; i++) {
			for (int j = i + 1; j < cnt; j++) {
				int diff = A[j] - A[i];
				int r = A[j];
				int count = 1;
				for (int k = j + 1; k < cnt; k++) {
					if (r + diff == A[k]) {
						r = A[k];
						count++;
						if (count >= 4) {
							f = true;
							break;
						}
					}
				}
				if (f)
					break;
			}
			if (f)
				break;
		}

		if (f)
			System.out.println("yes");
		else
			System.out.println("no");

	}

}
