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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.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class KingOfThieves {
	public static void main(String[] args) throws IOException {
		
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = Integer.parseInt(br.readLine());
		String map = br.readLine();
		
		int maxGap = (int) Math.floor((n - 5)/4);
		//System.out.println(maxGap);
		
		for (int i = 0; i <= maxGap; i++) {
			int maxRunSpace = i*4+5;
			
			for (int j = 0; j <= n - maxRunSpace; j++) { //starting platform
				if (map.charAt(j) == '.') {
					continue;
				} else {
					boolean possible = true;
					for (int k = j+i+1; k < j + maxRunSpace; k += i+1) {
						if (map.charAt(k) == '.') {
							possible = false;
							break;
						}
					}
					
					if (possible) {
						System.out.println("yes");
						System.exit(0);
					}
				}
			}
		}
		
		System.out.println("no");
	}
}