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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
// package CodeForces;

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

public class Problem_526A {
	public static boolean sol(int i,int sum,int diff)
	{
//		System.out.println(i);
		if(sum==4)
			return true;
		if(i==n || i==-1)
			return false;
		for(int j=i+1;j<n;j++)
		{
			if(s.charAt(j)=='*')
			{
				if(j-i==diff)
				{	
					if(sol(j,sum+1,diff))
						return true;
				}
				else
				{	
					if(sol(j,1,j-i))
						return true;
				}
			}
		}
		return false;
	}
	static int n;
	static String s;
	public static void main(String[] args) throws IOException {
		Scanner sc = new Scanner();
		PrintWriter pw = new PrintWriter(System.out);
		n=sc.nextInt();
		s=sc.nextLine();
		int i=s.indexOf("*");
		if(sol(i,0,-1))
			System.out.println("yes");
		else
			System.out.println("no");
		pw.close();
	}

	static class Scanner {
		BufferedReader br;
		StringTokenizer st;

		Scanner() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() throws IOException {
			while (st == null || !st.hasMoreTokens()) {
				st = new StringTokenizer(br.readLine());
			}
			return st.nextToken();
		}

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

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

		double nextDouble() throws IOException {
			return Double.parseDouble(next());
		}

		String nextLine() throws IOException {
			return br.readLine();
		}

		boolean hasnext() throws IOException {
			return br.ready();
		}

	}
}
