import java.util.Scanner;

public class SeriousOJChecker {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        int T = input.nextInt(); 
        input.nextLine();
        String target = "SeriousOJ";

        for (int t = 0; t < T; t++) {
            int N = input.nextInt(); 
            input.nextLine(); 
            String s = input.nextLine(); 

            if (s.contains(target)) {
                System.out.println("YES");
            } else {
                System.out.println("NO");
            }
        }

        input.close(); 
    }
}