#include<bits/stdc++.h>
#define rep(i,a,...) for(int i = (a)*(strlen(#__VA_ARGS__)!=0);i<(int)(strlen(#__VA_ARGS__)?__VA_ARGS__:(a));++i)
#define per(i,a,...) for(int i = (strlen(#__VA_ARGS__)?__VA_ARGS__:(a))-1;i>=(int)(strlen(#__VA_ARGS__)?(a):0);--i)
#define foreach(i, n) for(auto &i:(n))
#define pii pair<int, int>
#define pll pair<long long, long long>
#define all(x) (x).begin(), (x).end()
#define bit(x) (1ll << (x))
using ll = long long;
//const ll MOD = (ll)1e9+7;
const ll MOD = 998244353;
const int INF = (ll)1e9+7;
const ll INFLL = (ll)1e18;
using namespace std;
template<class t>
using vvector = vector<vector<t>>;
template<class t>
using vvvector = vector<vector<vector<t>>>;
template<class t>
using priority_queuer = priority_queue<t, vector<t>, greater<t>>;
template<class t, class u> bool chmax(t &a, u b){if(a<b){a=b;return true;}return false;}
template<class t, class u> bool chmin(t &a, u b){if(a>b){a=b;return true;}return false;}
#ifdef DEBUG
#define debug(x) cout<<"LINE "<<__LINE__<<": "<<#x<<" = "<<x<<endl;
#else
#define debug(x) (void)0
#endif

ll modpow(ll x, ll b){
  ll res = 1;
  while(b){
    if(b&1)res = res * x % MOD;
    x = x * x % MOD;
    b>>=1;
  }
  return res;
}

ll modinv(ll x){
  return modpow(x, MOD-2);
}

bool was_output = false;
template<class t>
void output(t a){
  if(was_output)cout << " ";
  cout << a;
  was_output = true;
}
void outendl(){
  was_output = false;
  cout << endl;
}
ll in(){
  ll res;
  scanf("%lld", &res);
  return res;
}

template<class t>
istream& operator>>(istream&is, vector<t>&x){
  for(auto &i:x)is >> i;
  return is;
}

template<class t, class u>
istream& operator>>(istream&is, pair<t, u>&x){
  is >> x.first >> x.second;
  return is;
}

template<class t>
void in(t&x){
  cin >> x;
}

template<class t>
void out(t x){
  cout << x;
}

vector<char> ins(){
  string str;
  in(str);
  vector<char> res;
  foreach(i,str){
    res.emplace_back(i=='o'?1:i=='-'?-1:0);
  }
  return res;
}

int count_ok_point(vector<char> line){
  int n = line.size();
  vector<bool> isok(n,false);
  int cnt = 0;
  int res = 0;
  rep(i,n){
    if(line[i]==1)++cnt;
    else if(line[i]==-1 and cnt>=2)isok[i]=true;
    else cnt=0;
  }
  cnt = 0;
  per(i,n){
    if(line[i]==1)++cnt;
    else if(line[i]==-1 and cnt>=2)isok[i]=true;
    else cnt=0;
  }
  rep(i,n)if(isok[i])++res;
  return res;
}

bool func(){
  int n = in();
  vector<char> isok = ins();
  {
    int cnt = 0;
    rep(i,n){
      if(isok[i]==1){
        if(++cnt>=3)return true;
      }
      else cnt=0;
    }
  }
  if(count_ok_point(isok)>=1)return true;
  rep(i,n){
    if(i==-1){
      isok[i] = 1;
      if(count_ok_point(isok)>=2)return true;
      isok[i] = -1;
    }
  }
  return false;
}

int main(){
  int n = in();
  rep(i,n){
    cout << (func()?"O":"X") << endl;
  }
  return 0;
}