#include<bits/stdc++.h>
using namespace std;

#define endl "\n"
#define trace(x) cout << #x << ": " << x << endl
int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t;
    cin >> t;
    while(t--)
    {
    	int n;
    	cin>>n;
        string s;
        cin>>s;
        string ans = "SeriousOJ";
        int i=0,j=0;
        while(1){
        	if(s[i]==ans[j])
        	{
        		i++;
        		j++;
        	}
        	else
        		i++;
        	if(j==ans.size()||i==s.size())
        		break;
        }
        if(j==ans.size())
        	cout<<"YES\n";
        else
        	cout<<"NO\n";
    }
    return 0;
}