// ---------- begin input macro ----------
// reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}
// ---------- end input macro ----------

fn run() {
    input! {
        n: usize,
        a: [usize; n],
    }
    let w = std::mem::size_of::<usize>() * 8;
    let mut sum = 0;
    let mut dp = vec![1usize];
    for a in a {
        sum += a;
        let mut next = vec![0; sum / w + 2];
        next[..dp.len()].copy_from_slice(&dp);
        let q = a / w;
        let r = a % w;
        if r == 0 {
            for (next, dp) in next[q..].iter_mut().zip(dp.iter()) {
                *next ^= *dp;
            }
        } else {
            for (i, dp) in dp.iter().enumerate() {
                next[i + q] ^= *dp << r;
                next[i + q + 1] ^= *dp >> (w - r);
            }
        }
        dp = next;
        dp.truncate(sum / w + 1);
    }
    let mut ans = 0;
    for i in 0..=sum {
        ans ^= (dp[i / w] >> i & 1) * i;
    }
    println!("{}", ans);
}

fn main() {
    run();
}