use std::io::Write;

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

    let mut t = vec!['a'; n];
    for i in 0..n {
        let scores = ('a'..'z')
            .map(|c| {
                t[i] = c;
                let ask = t.iter().collect::<String>();
                println!("? {}", ask);
                std::io::stdout().flush().unwrap();
                let score = {
                    let mut line = String::new();
                    std::io::stdin().read_line(&mut line).unwrap();
                    line.trim().parse::<usize>().unwrap()
                };

                score
            })
            .collect::<Vec<usize>>();

        if scores.iter().all(|&score| score == scores[0]) {
            t[i] = 'z';
        } else {
            let pos = (0..25).max_by_key(|&pos| scores[pos]).unwrap();
            t[i] = (b'a' + pos as u8) as char
        }
    }

    let ans = t.iter().collect::<String>();
    println!("! {}", ans);
}