#![allow(non_snake_case)]

use std::collections::HashSet;

use proconio::input;
use proconio::marker::Chars;

const INF: i64 = 1_000_000_000_000_000_000;

fn main() {
    input! {
        N: usize,
        mut A: [i64; N],
        mut B: [i64; N - 1],
    }

    A.sort();
    B.sort();

    let mut left = vec![0; N];
    let mut right = vec![0; N];
    for i in 0 .. N - 1 {
        left[i + 1] = left[i] + (A[i] - B[i]).abs();
        right[i + 1] = right[i] + (A[i + 1] - B[i]).abs();
    }

    let mut ans_set = HashSet::new();
    let mut ans_value = INF;
    for i in 0 .. N {
        let cost = left[i] - left[0] + right[N - 1] - right[i];
        if ans_value > cost {
            ans_value = cost;
            ans_set.clear();
        }
        if ans_value == cost {
            ans_set.insert(A[i]);
        }
    }

    let mut ans = ans_set.into_iter().collect::<Vec<_>>();
    ans.sort();

    println!("{}", ans.len());
    println!("{}", ans.iter().map(i64::to_string).collect::<Vec<_>>().join(" "));
}