use std::io::Read;

fn main() {
	let mut s = String::new();
	std::io::stdin().read_to_string(&mut s).ok();
	let mut n: u64 = s
		.split_whitespace()
		.skip(1)
		.flat_map(str::parse)
		.fold(0, |a, x: u64| a | x);
	let mut a = 1u64;
	while n & 1 == 1 {
		a *= 2;
		n >>= 1;
	}
	println!("{a}")
}