A = tuple(map(int, input().split()))

cnt_3 = 0
cnt_2 = 0
lst_2 = []

for i in range(9):
  cnt = 0
  for j in range(13):
    if A[j] == i+1:
      cnt += 1
  if cnt == 3:
    cnt_3 += 1
  elif cnt == 2:
    cnt_2 += 1
    lst_2.append(i+1)

if cnt_3 != 3 or cnt_2 != 2:
  print(0)
  exit()

lst_2.sort()

print(2)
print(*lst_2)