# answer is 43!
nuggets = []
# available sizes ordered from lowest to highest
size = [6,9,20]
# we know that 50 sets of McNuggets is possible
maximumSets = 50
# we will have to test at least maximum sets divided by lowest size
checkUpTo = maximumSets / size[0]

for i in range(0, checkUpTo):
  for j in range(0, checkUpTo):
    for k in range(0, checkUpTo):
      # we add all possible sizes being checked
      nuggets.append(i*size[0]+j*size[1]+k*size[2])

# we remove duplicates and sort
if nuggets:
    nuggets.sort()
    last = nuggets[-1]
    for i in range(len(nuggets)-2, -1, -1):
        if last == nuggets[i]:
            del nuggets[i]
        else:
            last = nuggets[i]

# at the beginning n is lowest possible nuggets size
n =  nuggets[0]
count = 1
for i in range(1,len(nuggets)-1):
  # we add + 1 to counter if next number is following after current
  if n + 1 == nuggets[i]:
    count += 1
  else:
    count = 1
  n = nuggets[i]
  # if next number follows current one 6 times we got answer
  if count == 6:
    print n-6
    break
  n = nuggets[i]