---

from functools import *


@lru_cache(None)
def g(n):
  if n <= 20:
    return n + 2
  if n > 20:
    return g(n - 3) + 1


def f(n):
  return 3 * g(n - 3) + 7


for n in range(38000):
  g(n)
print(f(37811))