#include<iostream>
#include<string>
#include<iomanip>
#include<cmath>
#include<vector>
#include<algorithm>
#include<utility>
#include<map>

using namespace std;

#define int long long
#define endl "\n"

constexpr long long INF = (long long)1e18;
constexpr long long MOD = 1'000'000'007; 

struct fast_io {
	fast_io(){
		std::cin.tie(nullptr);
		std::ios::sync_with_stdio(false);
	};
} fio;

bool solve(string &S){
	int N = S.size();
	
	int cono = count(S.begin(), S.end(), 'o');
	int conx =  count(S.begin(), S.end(), 'x');
	int con = 0;
	
	for(int i = 0; i < N - 2; i++){
		string x;
		
		x += S[i];
		x += S[i+1];
		x += S[i+2];
		
		if(x == "ooo") return true;
		if(x == "oo-") con++;
		if(x == "o-o") con++;
		if(x == "-oo") con++;
		
		if(i+3>=N)continue;
		
		x += S[i+3];
		
		// if(x == "-o--") return true;
		// if(x == "-o--") return true;
		if(x == "-o--")con++;
		if(x == "--o-") con++;
		
		if(i+4>=N)continue;
		
		x += S[i+4];
		
		if(x == "--o--") con--;
		if(x == "--o-o") con--;
		if(x == "o-o--") con--;
		if(x == "--oo-") con--;
		if(x == "-oo--") con--;
		
		if(x == "---oo") con--;
		if(x == "oo---") con--;
	}
	
	if(conx == cono && con) return true; 
	if(conx != cono && con >= 2) return true;
	
	return false;
}

map<string, int> field;

int check(string &S){
	int N = S.size();
	int cono= 0, conx = 0;
	
	for(int i = 0; i < N; i++){
		if(S[i] == 'x') conx++;
		else cono++;
	}
	
	if(cono < conx) return -1;
	if(cono - 1> conx) return -1;
	
	for(int i = 0; i < N - 2; i++){
		if(S[i] == 'o' && S[i+1] == 'o' && S[i+2] == 'o') return true;
	}
	
	return false;
}

int test(string &S, int t){
	int temp = field[S];
	
	if(temp != -1) return temp;
	
	bool flag = false;
	int con = 0;
	
	for(int i = 0; i < S.size(); i++){
		if(S[i] != '-') continue;
		con++;
		if(t) {
			S[i] = 'o';
			if(test(S, !t) == t) flag = true;
		} else {
			S[i] = 'x';
			if(test(S, !t) == t) flag = true;
		}
		
		S[i] = '-';
	}
	
	if(con == 0){
		field[S] = check(S);
	} else {
		if(flag) field[S] = t;
		else field[S] = !t;
	}
	return field[S];
}

void test2(int num){
	field.clear();
	string S;
	
	int x = 1;
	
	for(int i = 0; i < num; i++){
		x *= 3;
		S += '-';
	}
	
	for(int i = 0; i < x; i++){
		string z;
		int con = 0, d = i;
		
		for(int j = 0; j < num; j++, d /= 3){
			if(d%3 == 0) z += '-', con++;
			else if(d%3 == 1) z += 'o';
			else if(d%3 == 2) z += 'x';
		}
		
		field[z] = -1;
		
		// if(con) field[z] = -1;
		// else field[z] = check(z);
	}
	
	test(S, 1);
	
	int con = 0;
	
	for(int i = 0; i < x; i++){
		string z;
		int d = i;
		
		for(int j = 0; j < num; j++, d /= 3){
			if(d%3 == 0) z += '-';
			else if(d%3 == 1) z += 'o';
			else if(d%3 == 2) z += 'x';
		}
		// if(cono < conx) return -1;
		// if(cono - 1> conx) return -1;
		if(field[z] == 1) con++;
		// if(field[z] == 1)cout<<i<<" Z = "<<z<<" V = "<<field[z]<<endl;
		if(field[z] == -1) continue;
		
		// cout<<i<<" Z = "<<z<<" V = "<<field[z]<<" "<<solve(z)<<endl;
		if(field[z] != solve(z)){
			cout<<i<<" Z = "<<z<<" V = "<<field[z]<<" "<<solve(z)<<endl;
		}
	}
	
	cout<<"con = "<<con<<endl;
}

void test3(){
	int x; 
	
	cin>>x;
	
	test2(x);
}

signed main(){
	cout<<fixed<<setprecision(10);
	
	// test3();
	// return 0;
	
	int T;
	
	cin>>T;
	
	for(int _ = 0; _ < T; _++){
		int N;
		string S;
		
		cin>>N>>S;
		
		if(solve(S)) cout<<"O"<<endl;
		else cout<<"X"<<endl;
	}
	
	
	return 0;
}