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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.lang.*;
import java.io.*;
import java.util.*;


public class Thieves {
	
	public static void main(String[] args) throws java.lang.Exception {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		PrintWriter out = new PrintWriter(outputStream);
		TaskA solver = new TaskA();
		solver.solve(in, out);
		out.close();
	}
}

class TaskA {
	String s;
	int len;
	
	public void solve(InputReader in, PrintWriter out) {
		len = in.nextInt();
		s = in.next();
		
		for (int i=1; i<=len; ++i) {
			if (judge(i)) {
				out.println("yes");
				return ;
			}
		}
		out.println("no");
	}
	
	public boolean judge(int l) {
		int i, j, k;
		boolean flag;
		
		for (i=0; i<len; ++i) {
			flag = true;
			for (k=0,j=i; k<5; ++k,j+=l) {
				if (j >= len) {
					flag = false;
					break;
				}
				// System.out.print(j + " ");
				if (s.charAt(j) == '.') {
					flag = false;
					break;
				}
			}
			// System.out.println();
			if (flag) {
				return true;
			}
		}
		
		return false;
	}
}

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());
	}
	
	public long nextLong() {
		return Long.parseLong(next());
	}
}
