use std::io::Read;

fn main() {
	let mut s = String::new();
	std::io::stdin().read_to_string(&mut s).ok();
	let n: Vec<i8> = s.split_whitespace().flat_map(str::parse).collect();
	let (mut a, mut m) = (0, 11);
	for i in 1..=n[0] as usize {
		let d = (n[1] - n[i + 2]).abs();
		if d <= n[2] && d < m {
			(a, m) = (i, d);
		}
	}
	println!(
		"{}",
		if a > 0 {
			a.to_string()
		} else {
			"Unlucky!".to_owned()
		}
	);
}