#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <deque>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <complex>
#include <cmath>
#include <limits>
#include <climits>
#include <ctime>
#include <cassert>
#include <numeric>
#include <functional>
#include <bitset>

using namespace std;
using lint = long long int;
long long int INF = 1001001001001001LL;
int inf = 1000000007;
long long int MOD = 1000000007LL;
double PI = 3.1415926535897932;

template<typename T1,typename T2>inline void chmin(T1 &a,const T2 &b){if(a>b) a=b;}
template<typename T1,typename T2>inline void chmax(T1 &a,const T2 &b){if(a<b) a=b;}

#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()

/* do your best */

bool check(string s) {
  s = s + 'x';
  int n = s.size();

  for (int i = 0; i < n - 2; i++) {
    if (s.substr(i, 3) == "ooo") return true;
    if (s.substr(i, 3) == "o-o") return true;
    if (s.substr(i, 3) == "oo-") return true;
    if (i < n - 3 and s.substr(i, 4) == "-o--") return true;
    if (i < n - 4 and s.substr(i, 5) == "o---o") return true;
  }


  // o-----o など o（奇数長の-）o

  for (int i = 0; i < n; i++) {
    if (s[i] == 'o') {
      int cnt = 0;
      for (int j = i + 1; j < n; j++) {
        if (s[j] == '-') cnt++;
        else if (s[j] == 'x') break;
        else {
          if (cnt % 2 == 1) return true;
        }
      }
    }
  }

  return false;
}

int main() {
  
  int t; cin >> t;
  while (t--) {
    string s; cin >> s;
    cin >> s;
    string t = s;
    reverse(ALL(t));
    if (check(s) or check(t)) cout << "O" << endl;
    else cout << "X" << endl;
  }
  return 0;
}