use proconio::{input, source::line::LineSource};
use std::{
    collections::HashMap,
    io::{stdin, BufReader},
};

fn main() {
    let stdin = stdin();
    let mut source = LineSource::new(BufReader::new(stdin.lock()));

    input! {
        from &mut source,
        n: usize,
    }

    let mut base: Vec<_> = (0..n).map(|_| 'a').collect();

    for i in 0..n {
        let mut score = HashMap::new();

        // z なし
        for c in 'a'..'z' {
            let mut t = base.clone();
            t[i] = c;

            let text: String = t.iter().collect();

            println!("? {}", text);

            input! {
                from &mut source,
                hit: usize,
            }

            score.insert(hit, c);
        }

        if score.len() == 1 {
            base[i] = 'z';
        } else {
            let max_c = score.iter().max().unwrap();
            base[i] = *max_c.1;
        }
    }

    let text: String = base.iter().collect();

    println!("! {}", text);
}