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

int calc_win(int w, int l, int r) {
    if(w % 2 == 0) return 0;
    if(l == 1 && r == 1) return 1;
    else return 0;
}

int main() {
    int t;
    cin >> t;
    for(int tt = 0; tt < t; tt++) {
        int n;
        cin >> n;
        string s;
        cin >> s;
        bool win = false;
        for(int i = 1; i < n - 1; i++) {
            if(s[i - 1] == 'o' && s[i] == 'o' && s[i + 1] == 'o') win = true;
        }
        int w = 0, l = 0, r = 0;
        for(int i = 0; i < n; i++) {
            if(s[i] != '-') continue;
            w++;
            if(i == 0 || s[i - 1] != '-') {
                if(i && s[i - 1] == 'o') l = 1;
                if(i > 1 && s[i - 1] == 'o' && s[i - 2] == 'o') l = 2;
            }
            if(i == n - 1 || s[i + 1] != '-') {
                if(i < n - 1 && s[i + 1] == 'o') r = 1;
                if(i < n - 2 && s[i + 1] == 'o' && s[i + 2] == 'o') r = 2;
                if(l == 2 || r == 2) win = true;
                if(calc_win(w, l, r)) win = true;
                w = 0; l = 0; r = 0;;
            }
        }
        if(win) cout << "O" << endl;
        else cout << "X" << endl;
    }
    return 0;
}