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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.Scanner;
import java.util.Vector;
import java.util.*;

public class zeptolab {
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		int n=sc.nextInt();
		int temp=0;
		int temp1=0;
		char [] a=new char[n];
		Vector<Integer> b=new Vector<Integer>();
		String s=sc.next();
		a=s.toCharArray();
		for(int i=0;i<n;i++)
			if(a[i]=='*')
				b.add(i+1);
		int [] c=new int[b.size()];
		for(int i=0;i<b.size();i++)
			c[i]=b.get(i);
		for(int i=0;i<c.length;i++)
			for(int j=i+1;j<c.length;j++){
				temp = c[j]-c[i];
				int count=0;
				temp1=temp+c[j];
				while(count != 3 ){
					Arrays.sort(c);
				if(Arrays.binarySearch(c,temp1) >= 0)
				{
					temp1= temp1+temp;
					count++;
				}
				else
					break;
				}
					if(count==3)
					{
						System.out.println("yes");
						System.exit(0);
					}
			}
		System.out.println("no");
		
		
		
			
	}

}
