import sys
pin = sys.stdin.readline

def ST(): return pin().rstrip()
def IN(): return int(pin())
def IM(): return map(int, pin().split())
def IL(): return list(map(int, pin().split()))
def SR(n:int): return [pin().rstrip() for _ in range(n)]
def IMatrix(n:int): return [IL() for _ in range(n)]

##-----------------
import random
import math
import bisect
import itertools
from collections import defaultdict, deque
#from sortedcontainers import SortedList
##-----------------

N = IN()
A = IL()
B = IL()

A.sort()
B.sort()
S = sum([abs(A[i+1]-B[i]) for i in range(N-1)]) #一番小さい数を除外する場合
anslist = [A[0]]

for i in range(N-1):
	news = S + abs(A[i]-B[i]) - abs(A[i+1]-B[i])
	if news == S:
		anslist.append(A[i+1])
	elif news < S:
		anslist = [A[i+1]]
anslist = sorted(list(set(anslist)))

print(len(anslist))
print(*anslist)