#![allow(unused_imports)]
#![allow(non_snake_case)]
use std::collections::HashMap;
use std::collections::HashSet;
use std::collections::VecDeque;

#[allow(unused_macros)]
macro_rules! read {
    ([$t:ty] ; $n:expr) =>
        ((0..$n).map(|_| read!([$t])).collect::<Vec<_>>());
    ($($t:ty),+ ; $n:expr) =>
        ((0..$n).map(|_| read!($($t),+)).collect::<Vec<_>>());
    ([$t:ty]) =>
        (rl().split_whitespace().map(|w| w.parse().unwrap()).collect::<Vec<$t>>());
    ($t:ty) =>
        (rl().parse::<$t>().unwrap());
    ($($t:ty),*) => {{
        let buf = rl();
        let mut w = buf.split_whitespace();
        ($(w.next().unwrap().parse::<$t>().unwrap()),*)
    }};
}

#[allow(dead_code)]
fn rl() -> String {
    let mut buf = String::new();
    std::io::stdin().read_line(&mut buf).unwrap();
    buf.trim_end().to_owned()
}

fn main() {
    let d = read!(usize);
    let mut a = read!([isize]);

    if d <= 2 {
        let mut buf = String::new();
        buf.push_str(&format!("{}\n", d));
        for e in &a {
            buf.push_str(&format!("{} ", e));
        }
        println!("{}", &buf[..buf.len() - 1]);
    } else {
        for i in (3..=d).rev() {
            a[i - 2] += a[i];
        }
        match (a[0], a[1], a[2]) {
            (x, 0, 0) => {
                println!("0\n{}", x);
            }
            (x, y, 0) => {
                println!("1\n{} {}", x, y);
            }
            (x, y, z) => {
                println!("2\n{} {} {}", x, y, z);
            }
        }
    }
}