#!/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)