#!/bin/python3

import math
import os
import random
import re
import sys

# Complete the viralAdvertising function below.
def viralAdvertising(n):
    shared = 5
    liked = 2
    cumulative = 2
    for i in range(n-1):
        shared = (shared // 2) * 3
        liked = shared // 2
        cumulative = cumulative + liked
    return cumulative

if __name__ == '__main__':
    fptr = open(os.environ['OUTPUT_PATH'], 'w')

    n = int(input())

    result = viralAdvertising(n)

    fptr.write(str(result) + '\n')

    fptr.close()