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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.util.*;
public class Main {
public static void main(String [] args){
	Scanner in=new Scanner(System.in);
	int n=in.nextInt();
	String str=in.next();
	int start=0;
	for(int i=0;i<str.length();i++)
		if(str.charAt(i)=='*'){
		start=i;break;
		}
		//System.out.println(start);
		boolean flag=false;
		int seg=0;
	for(int i=0;i<str.length();i++){
		if(str.charAt(i)=='*')
			flag=true;
		if(str.charAt(i)!='*' && flag){
		seg++;flag=false;
		}	
	}
	if(n==1 && str.charAt(0)=='*'){
	System.out.print("yes");
	return;
	}
	//System.out.println(seg);
	for(int i=1;i<str.length();i++){
	    int ans=0;	
		for(int j=start;j<str.length();j+=i){
			if(str.charAt(j)=='*')ans++;
			else break;
		}
		if(ans==seg){
		System.out.print("yes");
		return;
		}
	}
	System.out.print("no");
}
}