def hanoi(n):
    if n<1:
        return -1
    elif n==1:
        return 1
    else:
        return 2*(hanoi(n-1))+1
num=int(input())
print(hanoi(num))

/**************************************************************
	Problem: 1223
	User: admin
	Language: Python
	Result: Accepted
	Time:103 ms
	Memory:34244 kb
****************************************************************/