#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int,int> pp;
const ll INF = 1e18;
const int MOD = 1000000007;
#define rep(i,n) for(int i=0;i<n;i++)

bool solve(int n,string s){
        rep(i,n-2){
                if(s[i] == '-' && s[i+1] == 'o' && s[i+2] == 'o'){
                        return true;
                }if(s[i] == 'o' && s[i+1] == 'o' && s[i+2] == '-'){
                        return true;
                }if(s[i] == 'o' && s[i+1] == 'o' && s[i+2] == 'o'){
                        return true;
                }if(s[i] == 'o' && s[i+1] == '-' && s[i+2] == 'o'){
                        return true;
                }
        }rep(i,n-4){
                if(s[i] == 'o' && s[i+1] == '-' && s[i+2] == '-' && s[i+3] == '-' && s[i+4] == 'o'){
                        return true;
                }if(s[i] == 'o' && s[i+1] == '-' && s[i+2] == '-' && s[i+3] == 'o' && s[i+4] == '-'){
                        return true;
                }if(s[i] == '-' && s[i+1] == 'o' && s[i+2] == '-' && s[i+3] == '-' && s[i+4] == 'o'){
                        return true;
                }
        }rep(i,n-3){
                if(s[i] == '-' && s[i+1] == 'o' && s[i+2] == '-' && s[i+3] == '-' ){
                        return true;
                }if(s[i] == '-' && s[i+1] == '-' && s[i+2] == 'o' && s[i+3] == '-' ){
                        return true;
                }
        }
        int cnt = 0;
        bool ok = false;
        rep(i,n){
                if(ok && cnt%2 == 1 && s[i] =='o') return true;
                if(s[i] == 'o') ok = true,cnt = 0;
                if(s[i] == 'x') ok = false,cnt = 0;
                if(s[i] == '-' && ok) cnt ++;
        }
        return false;
}

int main(){
        int t;
        cin >> t;
        while(t--){
                int n;
                string s;
                cin >> n >> s;
                cout << (solve(n,s) ? 'O' : 'X') << endl;
        }
        return 0;
}