fn query(x: usize) -> bool {
    println!("? {}", x);
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim() == "out"
}

fn run() {
    let mut ok = 0;
    let mut ng = 1000;
    while ng - ok > 1 {
        let mid = (ok + ng) / 2;
        if query(mid) && query(mid) {
            ng = mid;
        } else {
            ok = mid;
        }
    }
    let ans = if query(ok + 1) {
        ok + 1
    } else {
        ok
    };
    println!("! {}", ans);
}

fn main() {
    run();
}