#!/usr/bin/env python3
from ast import Call, parse, unparse, walk
from inspect import currentframe, getsourcelines
from sys import stdin

_tokens = (y for x in stdin for y in x.split())
def read(): return next(_tokens)
def iread(): return int(next(_tokens))


def dprint(*args, pretty=True):
    def _inner(v):
        def _format_3d(v): return '\n' + '\n'.join(['\n'.join([' '.join([str(z) for z in y]) for y in x]) + '\n' for x in v]).rstrip('\n')
        def _format_2d(v): return '\n' + '\n'.join([' '.join([str(y) for y in x]) for x in v])
        def _dim(v): return (1 + min(_dim(x) for x in v) if v else 1) if isinstance(v, (list, tuple)) else 1 if isinstance(v, str) and len(v) > 1 else 0
        dim = _dim(v) if pretty else -1
        return _format_3d(v) if dim == 3 else _format_2d(v) if dim == 2 else str(v)
    frame = currentframe().f_back
    source_lines, start_line = getsourcelines(frame)
    tree = parse(source_lines[frame.f_lineno - max(1, start_line)].strip())
    call_node = next(node for node in walk(tree) if isinstance(node, Call) and node.func.id == 'dprint')
    arg_names = [unparse(arg) for arg in call_node.args]
    print(', '.join([f'\033[4;35m{name}:\033[0m {_inner(value)}' for name, value in zip(arg_names, args)]))


def main():
    n = iread()
    a = [iread() for _ in range(n)]
    b = [iread() for _ in range(n - 1)]
    a.sort()
    b.sort()
    # dprint(a)
    # dprint(b)
    tot = 0
    for u, v in zip(a, b):
        tot += abs(u - v)
    min_ = tot
    for i in range(n - 2, -1, -1):
        tot -= abs(a[i] - b[i])
        tot += abs(a[i + 1] - b[i])
        min_ = min(min_, tot)
    # dprint(min_)
    ans = set()
    tot = 0
    for u, v in zip(a, b):
        tot += abs(u - v)
    # dprint(tot)
    if tot == min_:
        ans.add(a[n - 1])
    for i in range(n - 2, -1, -1):
        tot -= abs(a[i] - b[i])
        tot += abs(a[i + 1] - b[i])
        if tot == min_:
            ans.add(a[i])
        # dprint(min_, tot, ans)
    ans = sorted(ans)
    print(len(ans))
    print(*ans)


if __name__ == '__main__':
    main()