use std::io::Read;

fn main() {
	let mut s = String::new();
	std::io::stdin().read_to_string(&mut s).ok();
	let (mut b, mut e) = (vec![], vec![]);
	s.split_whitespace()
		.skip(1)
		.collect::<Vec<_>>()
		.chunks(2)
		.for_each(|v| match v[0] {
			"1" => b.push(v[1]),
			_ => e.push(v[1]),
		});
	b.reverse();
	println!("{}{}", b.join(""), e.join(""))
}