//#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
#define rep(i, n) for(int i=0; i<n; ++i)
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
using namespace std;
using ll = int64_t;
using ld = long double;
using P = pair<int, int>;
using vs = vector<string>;
using vi = vector<int>;
using vvi = vector<vi>;
template<class T> using PQ = priority_queue<T>;
template<class T> using PQG = priority_queue<T, vector<T>, greater<T> >;
const int INF = 0xccccccc;
const ll LINF = 922337203685477580LL;
template<typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true);}
template<typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true);}
template<typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) { return is >> p.first >> p.second;}
template<typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) { return os << p.first << ' ' << p.second;}



//head



int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int t;
	cin >> t;
	while(t--) {
		int n;
		string s;
		cin >> n >> s;
		bool win = false;
		bitset<1000> bits;
		rep(u, 2) {
			bits = 0;
			rep(i, n) {
				if(bits.test(i)) s[i] = 'o';
				if(n-i >= 3) {
					if(s.substr(i, 3) == "oo-" or s.substr(i, 3) == "-oo" or s.substr(i, 3) == "o-o" or s.substr(i, 3) == "ooo") win = true;
					if(s.substr(i, 3) == "o--") bits.set(i+2);
				}
				if(n-i >= 4) {
					if(s.substr(i, 4) == "-o--" or s.substr(i, 4) == "--o-") win = true;
				}
				if(bits.test(i)) s[i] = '-';
			}
			reverse(all(s));
		}
		cout << (win?"O":"X") << '\n';
	}
}