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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
/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
 
/* Name of the class has to be "Main" only if the class is public. */
public class bbg
{
	public static int result;
 
public static ArrayList<Integer> [] graph;
 
public static int[]cats;
 
public static int vizitat[];
public static int x;
//public static HashMap<String, Integer> map2;
 
 
	public static void main (String[] args) throws java.lang.Exception
{
 
Scanner input=new Scanner(System.in);
 
HashMap<Integer, Integer> contor1= new HashMap<Integer, Integer>();
HashMap<Integer, Integer> contor2= new HashMap<Integer, Integer>();


HashMap<Integer, Integer> map= new HashMap<Integer, Integer>();
HashMap<String, Integer> curatare= new HashMap<String, Integer>();
HashMap<String, Integer> combinari= new HashMap<String, Integer>();
 
 
		
		
		String nn=input.next();
		int n=Integer.parseInt(nn);
		
		String str=input.next();
		
		String v[]=new String[n];
		int s[]=new int[n];
		String a;
		
		

	int y=0;
	
	
		for(int i=0;i<str.length();i++)
		
		if(str.substring(i,i+1).equals("*")) s[i]=1;
		
	//	for(int i=0;i<n;i++) System.out.print(s[i]);
		
	for(int i=0;i<n;i++)
	if(s[i]==1){
	    
	    
	
	for(int j=1;j<=100;j++)
	{int contor=1;
	for(int x=1;x<=5;x++){
	    
	  
	    
	    int part=i+j*x;
	    
	    if(i+j*x<n) {if(contor<5 && s[i+j*x]==0) contor=0;
	   
	    else if(s[part]==1) {contor++;
	        
	       // System.out.println(i+" "+part+" "+contor);
	    }
	     if(contor>=5) y=1;
	     
	     
	     
	    }
	    
	}
	
}
	
	}
	
	if(y==0) System.out.println("no");
	else System.out.println("yes");
		
		}
		
		
		}
		
		