fn main() {
    let mut n = String::new();
    std::io::stdin().read_line(&mut n).ok();
    let n: usize = n.trim().parse().unwrap();
    let mut a = String::new();
    std::io::stdin().read_line(&mut a).ok();
    let a: Vec<usize> = a.trim().split_whitespace().map(|s| s.parse().unwrap()).collect();

    if n > 15 {
        println!("{}", (1usize << 16) - 1);
        return;
    }
    let mut dp = vec![vec![false; 1<<16]; n+1];
    dp[0][0] = true;
    for i in 0..n {
        for j in 0..1<<16 {
            if !dp[i][j] { continue; }
            let mut val = a[i];
            for _ in 0..=16 {
                dp[i+1][j|val] = true;
                val = val / 2 + if val & 1 == 1 { 1 << 15 } else { 0 };
            }
        }
    }
    println!("{}", dp[n].iter().enumerate().filter(|&(_, &v)| v).map(|(i, _)| i).max().unwrap());
}