#![allow(unused_imports)]
#![allow(non_snake_case)]
use std::cmp::*;
use std::collections::*;
use std::io::Write;

#[allow(unused_macros)]
macro_rules! debug {
    ($($e:expr),*) => {
        #[cfg(debug_assertions)]
        $({
            let (e, mut err) = (stringify!($e), std::io::stderr());
            writeln!(err, "{} = {:?}", e, $e).unwrap()
        })*
    };
}

fn main() {
    let n = read::<usize>();
    for i in 0..n {
        let v = read_vec::<String>();
        let s = &v[1].chars().collect::<Vec<_>>();

        if s.len() < 3 {
            println!("X");
            continue;
        }

        let mut found = false;
        for i in 0..s.len() - 2 {
            if s[i] == 'o' && s[i + 1] == 'o' && s[i + 2] == 'o' {
                found = true;
            }
            if s[i] == 'o' && s[i + 1] == 'o' && s[i + 2] == '-' {
                found = true;
            }
            if s[i] == '-' && s[i + 1] == 'o' && s[i + 2] == 'o' {
                found = true;
            }
        }
        for i in 0..s.len() - 3 {
            if s[i] == '_' && s[i + 1] == 'o' && s[i + 2] == '_' && s[i + 3] == '_' {
                found = true;
            }
            if s[i] == '_' && s[i + 1] == '_' && s[i + 2] == 'o' && s[i + 3] == '_' {
                found = true;
            }
        }
        let mut spans = vec![];
        for i in 0..s.len() {
            if s[i] != '-' {
                continue;
            }
            if i == 0 || s[i - 1] != '-' {
                spans.push((i, i));
            } else {
                let idx = spans.len() - 1;
                spans[idx].1 = i;
            }
        }
        for (start, end) in spans {
            if start == 0 || end == s.len() - 1 || (end - start) % 2 == 1 {
                continue;
            }
            if s[start - 1] == 'o' && s[end + 1] == 'o' {
                found = true;
            }
        }
        if found {
            println!("O");
        } else {
            println!("X");
        }
    }
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}