fn main() {
    let t = {
        let mut line = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        line.trim().parse::<usize>().unwrap()
    };

    for _ in 0..t {
        if let Some(ans) = solve() {
            println!("{}", ans);
        } else {
            println!("-1");
        }
    }
}

fn solve() -> Option<String> {
    let _n = {
        let mut line = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        line.trim().parse::<usize>().unwrap()
    };
    let s: Vec<char> = {
        let mut line = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        line.trim().chars().collect()
    };

    let target_chars: Vec<char> = "helloworld".chars().collect();

    let is_match = |start_idx: usize| {
        for (i, &c) in target_chars.iter().enumerate() {
            if s[start_idx + i] != '?' && s[start_idx + i] != c {
                return false;
            }
        }

        true
    };

    for start_idx in (0..(s.len() - target_chars.len() + 1)).rev() {
        if is_match(start_idx) {
            let mut ans: Vec<char> = s.iter().map(|&c| if c == '?' { 'a' } else { c }).collect();

            for i in 0..target_chars.len() {
                ans[start_idx + i] = target_chars[i];
            }

            return Some(ans.iter().collect());
        }
    }

    None
}