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p = list(range(17, 59))
q = list(range(29, 81))
a = []
for x in range(1, 1000):
  if (
      (x in p)
      <= (((x in q) and (x not in a)) <= (x not in p))
  ) == 0:
    a.append(x)
print(max(a) - min(a))