use std::{
    cell::RefCell,
    fmt::Debug,
    io::{BufWriter, StdinLock, StdoutLock, stdin, stdout},
    str::FromStr,
};

fn main() {
    let [n, s, k] = read_tuple();
    let mut a = vec![];
    for _ in 0..n {
        a.push(read::<i32>());
    }

    let mn = *a.iter().min_by_key(|x| x.abs_diff(s)).unwrap();

    if mn.abs_diff(s) > k as u32 {
        println!("Unlucky!");
    } else {
        println!("{}", a.iter().position(|x| *x == mn).unwrap() + 1);
    }
}

thread_local! {
    static STDIN: RefCell<StdinLock<'static>> = RefCell::new(stdin().lock());
    static STDOUT: RefCell<BufWriter<StdoutLock<'static>>> = RefCell::new(BufWriter::new(stdout().lock()));
}

#[allow(dead_code)]
fn read<T: FromStr>() -> T
where
    <T as FromStr>::Err: Debug,
{
    read_line().parse().unwrap()
}

#[allow(dead_code)]
fn read_vec<T: FromStr>() -> Vec<T>
where
    <T as FromStr>::Err: Debug,
{
    read_line()
        .split_whitespace()
        .map(|x| x.parse().unwrap())
        .collect()
}

#[allow(dead_code)]
fn read_tuple<T: FromStr, const N: usize>() -> [T; N]
where
    T: Debug,
    <T as FromStr>::Err: Debug,
{
    read_vec::<T>().try_into().unwrap()
}

fn read_line() -> String {
    use std::io::BufRead;
    let mut s = String::new();
    STDIN.with(|cell| {
        cell.borrow_mut().read_line(&mut s).unwrap();
    });
    String::from_str(s.trim_end()).unwrap()
}

#[macro_export]
macro_rules! print {
    ($($t:tt)*) => {
        use std::io::Write;
        STDOUT.with(|cell| write!(cell.borrow_mut(), $($t)*).unwrap())
    };
}

#[macro_export]
macro_rules! println {
    ($($t:tt)*) => {
        use std::io::Write;
        STDOUT.with(|cell| writeln!(cell.borrow_mut(), $($t)*).unwrap())
    };
}