#![allow(unused_imports)]
use std::cmp::*;
use std::collections::*;
use std::io::Write;
use std::ops::Bound::*;

#[allow(unused_macros)]
macro_rules! debug {
    ($($e:expr),*) => {
        #[cfg(debug_assertions)]
        $({
            let (e, mut err) = (stringify!($e), std::io::stderr());
            writeln!(err, "{} = {:?}", e, $e).unwrap()
        })*
    };
}

fn shift(x: usize) -> usize {
    x / 2 + (x % 2) * (1 << 15)
}

fn main() {
    let n = read::<usize>();
    let a = read_vec::<usize>();
    if n > 16 {
        println!("65535");
        return;
    }
    let mut dp = vec![false; 65536];
    dp[0] = true;
    for aa in a {
        let mut next = dp.clone();
        let mut cur = aa;
        for _ in 0..16 {
            for prev in 0..65536 {
                next[prev | cur] |= dp[prev];
            }
            cur = shift(cur);
        }
        dp = next;
    }
    for i in (0..65536).rev() {
        if dp[i] {
            println!("{}", i);
            return;
        }
    }
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}