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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;

public class ZeptoVP_A {
	public static void main(String[] args) {
		Scanner s = new Scanner(System.in);
		int num = s.nextInt(); s.nextLine();
		int[] freq = new int[num+1];
		String line = s.nextLine();
		for(int i = 0; i < line.length(); i++) {
			if(line.charAt(i) == '*' && i != line.length()-1) {
//				System.out.println("RUNS?");
				int j = i+1;
				int count = 1;
				while(j < line.length()) {
					if(line.charAt(j) == '*') {
						freq[count]++;
						if(freq[count] == 4) {
							System.out.println("yes");
//							for(int k = 0; k < freq.length; k++) System.out.print(freq[k] + " ");
							return;
						}
					}
					j++;
					count++;
				}
				
//				System.out.println("COUNT: " + count);
			}
		}
		System.out.println("no");
//		for(int k = 0; k < freq.length; k++) System.out.print(freq[k] + " ");
	}
}
