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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;

public class Thief
{
	public boolean good(int segments, String seg, int l)
	{
		int good = 0;
		int index = -1;
		boolean isGood = false;

		if(segments < 4)
		{
			return false;
		}

		for (int i = 0; i < l; i++) 
		{
			while(!isGood && index < segments)
			{
				if (index == -1)
				{
					if(seg.charAt(0) == '*')
					{
						good ++;
						if(good == 4)
							isGood = true;
							return true;
							
					}
					else
						good = 0;
					index = index + l;
				}
				else
				{

					if(seg.charAt(index) == '*')
					{
						good ++;
						if(good == 4)
							isGood = true;
							return true;
					}
					else
						good = 0;
					index = index + l;
				}
			}
		}
		return isGood;
	}
	public static void main(String[] args)
	{
		int segments;
		boolean good = false;
		Scanner sc = new Scanner(System.in);
		segments = sc.nextInt();
		String seg = new String();
		seg = sc.next();
		Thief game = new Thief();
		int l = segments / 4;
		for (int i = 1; i <= l; i++)
		{
			if(game.good(segments, seg, i)) 
			{
				good = true;
				i = l+1;
			}
			else
			{
				good = false;
			}
		}
		if(good) 
			System.out.println("yes");
		else
			System.out.println("no");
	}
}