use std::io::Write;

use proconio::input_interactive;

fn main() {
    input_interactive!(alpha: char);

    let mut prev = alpha;
    loop {
        println!("? {}{}", prev, prev);
        std::io::stdout().flush().unwrap();

        let mut line = String::new();
        std::io::stdin().read_line(&mut line).unwrap();
        let split_line = line.split_whitespace().collect::<Vec<_>>();

        if split_line[0] == "!" {
            break;
        }

        prev = split_line[1].chars().last().unwrap();
    }
}