import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std.typecons;
import core.bitop;

class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens.popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }

bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }

int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1; (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }


bool checkPart(string part) {
  const len = cast(int)(part.length);
  const o = part.count('o');
  bool ret;
  switch (o) {
    case 0: {
      ret = false;
    } break;
    case 1: {
      ret = (len >= 3 && part[0] == '-' && part[len - 1] == '-');
    } break;
    case 2: {
      ret = !(len % 2 == 0 && part[0] == 'o' && part[len - 1] == 'o');
    } break;
    default: {
      ret = true;
    }
  }
  return ret;
}

bool check(string board) {
  auto parts = board.split("x");
  bool ret;
  foreach (part; parts) {
    if (checkPart(part)) {
      ret = true;
    }
  }
  return ret;
}

void main() {
  debug {
    enum lim = 13;
    foreach (n; 1 .. lim + 1) {
      auto dp = new bool[3^^n];
      foreach_reverse (p; 0 .. 3^^n) {
        const board = iota(n).map!(i => "-ox"[p / 3^^i % 3]).array;
        const diff = board.count('o') - board.count('x');
        if (board.count('-') == 0) {
          // done
          foreach (i; 0 .. n - 3 + 1) {
            if (board[i .. i + 3] == "ooo") {
              dp[p] = true;
            }
          }
        } else if (diff == 0) {
          // o
          foreach (i; 0 .. n) {
            if (board[i] == '-') {
              if (dp[p + 3^^i]) {
                dp[p] = true;
              }
            }
          }
        } else if (diff == 1) {
          // x
          dp[p] = true;
          foreach (i; 0 .. n) {
            if (board[i] == '-') {
              if (!dp[p + 2 * 3^^i]) {
                dp[p] = false;
              }
            }
          }
        } else {
          continue;
        }
        if (diff == 0 && dp[p]) {
          if (dp[p]) {
            writeln(board, ": ", diff, " ", dp[p]);
          }
          const res = check(board);
          assert(dp[p] == res, format("FAIL %s: %s %s", board, dp[p], res));
        }
      }
    }
  }
  
  try {
    for (; ; ) {
      const numCases = readInt();
      foreach (caseId; 0 .. numCases) {
        const N = readInt();
        const S = readToken();
        const ans = check(S);
        writeln(ans ? "O" : "X");
      }
    }
  } catch (EOFException e) {
  }
}