#include <iostream>
#include <string>
using namespace std;

// Function to check if "SeriousOJ" is a subsequence of S
bool isSubsequence(const string& S, const string& target) {
    int targetIndex = 0;
    int targetLen = target.length();
    
    for (char ch : S) {
        if (ch == target[targetIndex]) {
            targetIndex++;
            if (targetIndex == targetLen) {
                return true;
            }
        }
    }
    return false;
}

int main() {
    int T;
    cin >> T; // Number of test cases
    
    string target = "SeriousOJ";
    string result;
    
    while (T--) {
        int N;
        cin >> N; // Length of the string S
        string S;
        cin >> S;
        
        if (isSubsequence(S, target)) {
            result += "YES\n";
        } else {
            result += "NO\n";
        }
    }
    
    cout << result;
    return 0;
}