#include <iostream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstdlib>
#include <cassert>
#include <vector>
#include <list>
#include <stack>
#include <queue>
#include <deque>
#include <map>
#include <set>
#include <bitset>
#include <string>
#include <algorithm>
#include <utility>
#define llint long long
#define inf 1e18
#define rep(x, s, t) for(llint (x) = (s); (x) < (t); (x)++)
#define Rep(x, s, t) for(llint (x) = (s); (x) <= (t); (x)++)
#define chmin(x, y) (x) = min((x), (y))
#define chmax(x, y) (x) = max((x), (y))

using namespace std;
typedef pair<llint, llint> P;

llint T;
llint n; string s;

bool calc(llint l, llint r)
{
	if(r-l+1 < 3) return false;
	
	llint cnt = 0;
	for(int i = l; i <= r; i++){
		if(s[i] == 'o') cnt++;
		else{
			if(cnt >= 2) return true;
			cnt = 0;
		}
	}
	if(cnt >= 2) return true;
	
	bool flag[2] = {};
	for(int i = l; i <= r; i++){
		if(s[i] != 'o') continue;
		if(i-1 >= l && i+2 <= r && s[i-1] == '-' && s[i+1] == '-' && s[i+2] == '-') return true;
		if(i-2 >= l && i+1 <= r && s[i-2] == '-' && s[i-1] == '-' && s[i+1] == '-') return true;
		if(flag[i%2]) return true;
		flag[i%2] = true;
	}
	return false;
}

int main(void)
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	
	cin >> T;
	for(int t = 0; t < T; t++){
		cin >> n >> s;
		
		llint l = 0; bool ans = false;
		for(int i = 0; i < s.size(); i++){
			if(s[i] == 'x'){
				ans |= calc(l, i-1);
				//if(calc(l, i-1)) cout << l << " " << i-1 << endl;
				l = i+1;
			}
		}
		ans |= calc(l, n-1);
		if(ans) cout << "O" << endl;
		else cout << "X" << endl;
	}
	
	return 0;
}