#include <bits/stdc++.h>
#define rep(i,a,b) for(int i=a;i<b;i++)
#define fore(i,a) for(auto &i:a)
using namespace std;
using ll = long long;
const ll mod = 1000000007;

#define yes "O"
#define no "X"
int N;
string S;

string solve() {
  cin >> N >> S;

  vector<string> wins = {"ooo", "oo-", "-oo", "--o-", "-o--"};
  fore (win, wins) rep (i, 0, N) if (S.substr(i, win.size()) == win) return yes;

  vector<int> okvec;
  rep (i, 0, N) if (S[i] == 'o') okvec.push_back(i);

  int r = okvec.size();
  rep (i, 0, r - 1) {
    int s = okvec[i];
    int e = okvec[i + 1];
    int lose = 0;
    int blank = 0;
    rep (j, s + 1, e) {
      if (S[j] == 'x') lose++;
      else blank++;
    }
    if (lose == 0 && blank % 2 == 1) return yes;
  }
    return no;
}

int main() {
  int T;
  cin >> T;
  rep (i, 0, T) cout << solve() << endl;
}