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***************************************************************************************************
 5
****.

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;
import java.io.PrintWriter;
import java.util.StringTokenizer;


public class Main {
	static int [][][] dp ;
	static int n ; 
	static char [] array;
	
	private static int fill(int index,int platforms,int jump) {
		
		if(platforms == 4) return 1;
		
		if(index+jump >=n) return 0;


		if(dp[index][platforms][jump]!=-1) return dp[index][platforms][jump];
		
		int answer = 0;
		
			if(array[index+jump]=='*')
				answer = Math.max(answer, fill(index+jump, platforms+1,jump));
		
		return dp[index][platforms][jump] = answer;
	}
	private static void solve() {

		
		 n = nextInt();
		
	  array = next().toCharArray();
		
		dp = new int [100][4][26];
		
		for(int i=0;i<dp.length;i++)
			for(int j=0;j<dp[i].length;j++)
				for(int k=0;k<=25;k++)
				dp[i][j][k] = -1;
		
		int answer = 0;
		for(int i=0;i<array.length-1;i++){
			if(array[i] == '*') {
				for(int nata = 1;nata<=25;nata++)
			answer = Math.max(answer,fill(i,0,nata));
			
			}
		}
		
		out.println(answer == 0 ? "no":"yes");
	}
	
    private static void run() {
        br = new BufferedReader(new InputStreamReader(System.in));
        out = new PrintWriter(System.out);

        solve();

        out.close();
    }

    private static StringTokenizer st;
    private static BufferedReader br;
    private static PrintWriter out;

    private static String next() {
        while (st == null || !st.hasMoreElements()) {
            String s;
            try {
                s = br.readLine();
            } catch (IOException e) {
                return null;
            }
            st = new StringTokenizer(s);
        }
        return st.nextToken();
    }

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

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

    public static void main(String[] args) {
        run();
    }
}
