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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.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class a {

    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        s.nextInt();
        String s1=s.next();
        int n=0;
        for(int i=0;i<s1.length();i++)
            if(s1.charAt(i)=='*')
                n++;
        int a[]=new int[n];
        int j=0;
        for(int i=0;i<s1.length();i++)
           if(s1.charAt(i)=='*')
              a[j++]=i+1; 
        int b[]=new int[(n*(n-1))/2];
        j=0;
        for(int i=0;i<n;i++)
          for(int j1=i+1;j1<n;j1++)
            b[j++]=a[j1]-a[i];
        Arrays.sort(b);
        int flag=0;
        for(int i=0;i<b.length-3;i++)
          if(b[i]==b[i+1]&&b[i]==b[i+2]&&b[i]==b[i+3]&&b[i]!=0){
             flag=1;
             break;
          }
        
        if(flag==1)
            System.out.println("yes");
        else
            System.out.println("no");
    }
}

