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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.util.Scanner;

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */

/**
 *
 * @author Al_Deeb
 */
public class ss {
    
    public static void main (String []args)
    {
        Scanner sc=new Scanner(System.in);
        
        int n=sc.nextInt();
        String s=sc.next();
      char[] f=s.toCharArray();
      
       // System.out.println(s);
      int max=n/4;
      int ff=1;
        for (int i = 0; i < n; i++) {
            
            if(f[i]=='*')
            {
                for (int j = i+1; j < max+i; j++) {
                    int len =j-i;
                    if(f[j]=='*')
                    {
                        for (int k = 1; k <= 3; k++) {
                            
                            if((j+len*k)>n||f[j+len*k]=='.')
                            { 
                                ff=0;
                                break;
                            }
                            else
                                ff=2;
                        }
                        if(ff==2)
                            break;
                    }
                }
                
                if(ff==2)
                            break;
            }
            
        }
  
        if(ff==2)
            System.out.println("yes");
        else
            System.out.println("no");
        
        
    }
    
}
