#!/bin/python3

import sys

def sumOfGroup(k):
    # Return the sum of the elements of the k'th group.
    i=4
    l=[[],[1],[3,5],[7,9,11]]

    #13 15 17 19 #21 23 25 27 29
    while i<k:
        x=len(l[i-1])
        y=l[i-1][-1]
        l[i]=[x+2 for x in range(y,x*2)+2]
    sum=0
    for i in range(k):
        sum+=l[k][i]
    return sum
if __name__ == "__main__":
    k = int(input().strip())
    answer = sumOfGroup(k)
    print(answer)