#!/usr/bin/env python3

from math import factorial

def bin(n, k):
    return factorial(n) // (factorial(n-k) * factorial(k))

def late(n):
    return 3**n - 2**n - 2**(n-1) * n

def absent2(n):
    if n < 3:
        return 0
    middle = (n-3) * 2**(n-4) - sum(2**(n-4-i) * absent(i) for i in range(n-3))
    left  = sum(2**(n-4-i) * (i * 2**(i-1)  -  absent2(i)) for i in range(n-3))
    right = (n-3) * 2**(n-4) + sum((n-3-i) * 2**(n-4-i) * (2**(i-1)  -  absent(i-1)) for i in range(1, n-3))
    return right + left + middle

def absent(n):
    if n < 3:
        return 0
    return 2**(n-3) + (n-3) * 2**(n-4) - sum(2**(n-4-i) * absent(i) for i in range(n-3))

n = 30

print(int(3**n - late(n) - absent(n) - absent2(n)))