#!/usr/bin/env python3
lim = 10**12
x, y = 3, 1
blue = 3
total = 4
while total <= lim:
x, y = 3*x + 8*y, 3*y + x
blue = (2*y + x + 1) // 2
total = (4*y + x + 1) // 2
print(blue)