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


public class A {
	 public static void main(String[] args) throws IOException {
	        //BufferedReader in = new BufferedReader(new FileReader("input.txt"));
	    	BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
	        PrintWriter out = new PrintWriter(new OutputStreamWriter(System.out));
	        StringTokenizer str;

	        str = new StringTokenizer(in.readLine());
	        int n = Integer.parseInt(str.nextToken());
	        
	        boolean ans = false;
	        String s = in.readLine();
	        for (int i=0; i<n; i++) {
	        	for (int j=1; j<s.length()/3; j++) {
	        		boolean temp = true;
	        		for (int k=0; k<5; k++) {
	        			if ((i+k*j) >= n || s.charAt(i+k*j) == '.') temp = false; 
	        		}
	        		if (temp) ans = temp;
	        	}
	        }
	        if (ans) out.println("yes");
	        else out.println("no");
	        
	        out.flush();
	 }
}
