use std::io::Read;

fn main() {
    let mut buf = String::new();
    std::io::stdin().read_to_string(&mut buf).unwrap();
    
    let mut iter = buf.split_whitespace();
    
    let d: usize = iter.next().unwrap().parse().unwrap();
    let mut p: Vec<i32> = iter.map(|n| n.parse::<i32>().unwrap()).collect();
    
    for i in (3..=d).rev() {
        p[i-2] += p[i];
        p[i] = 0;
    }
    
    for i in (0..=3).rev() {
        if p[i] != 0 {
            println!("{}", i);
            for j in 0..i {
                print!("{} ", p[j]);
            }
            println!("{}", p[i]);
            return;
        }
    }
    
    println!("0\n0");
}