def main():
  N = int(input())
  A = list(map(int, input().split()))
  B = list(map(int, input().split()))

  A.sort()
  B.sort()
  L = [0] * N
  R = [0] * N
  for i in range(N-1):
    L[i+1] = L[i] + abs(A[i] - B[i])
  for i in range(1, N):
    R[-i-1] = R[-i] + abs(A[-i] - B[-i])

  m = min(L[i]+R[i] for i in range(N))
  ans = {A[i] for i in range(N) if L[i]+R[i] == m}
  print(len(ans))
  print(*sorted(ans))

main()