import sys

# Input: n the number of disks
# Output: returns the number of transfers using four needles
def num_moves (n):
  return

def main():
  # read number of disks and print number of moves
  for line in sys.stdin:
    line = line.strip()
    num_disks = int (line)
    print (num_moves (num_disks))

if __name__ == "__main__":
  main()