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

cnt_3 = 0
cnt_2 = 0
lst_2 = []
cnt_1 = 0
lst_1 = []

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)
  elif cnt == 1:
    cnt_1 += 1
    lst_1.append(i+1)

if cnt_3 == 3 and cnt_2 == 2:
  lst_2.sort()
  print(2)
  print(*lst_2)
  exit()
  
if cnt_3 == 4 and cnt_1 == 1:
  print(1)
  print(*lst_1)
  exit()

print(0)
print("")