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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 Tester 
{
	public static void main(String[] args) 
	{
		Scanner sc = new Scanner(System.in);
		
		int a = 0,b = 0;
		int n=Integer.parseInt(sc.nextLine());
		String str=sc.next();
		char arr[]=str.toCharArray();
		
		if(arr.length==n)
		{
			for(int i=0;i<arr.length;i++)
			{
				if(arr[i]=='*')
				{
					a=i;
					for(int j=i+1;j<arr.length;j++)
					{
						if(arr[j]=='*')
						{
							b=j;
							if(b-a==1 && arr.length!=5)
								continue;
							else
								break;
						}
					}
					break;
				}
			}
			//System.out.println(a+" "+b);
			//System.out.println(b-a);
			int counter=0;
			
			for(int i=a;i<arr.length;i=i+(b-a))
			{
				if(arr[i]=='*')
				{
					counter++;
					//System.out.print(i+" ");
				}
				else if(arr[i]=='.')
				{
					counter=0;
					break;
				}
					
			}
			//System.out.println();
			//System.out.println(counter);
			
			if(counter==5)
				System.out.println("yes");
			else
				System.out.println("no");
		}
	}
}
