n = int(input())
cnt = 0

def mult(*n):
    result = 1
    for i in n:
        result *= n
    return result

def conb(l, r):
    if r == 0: return 1
    result = 1
    for x in range(l, l - r, -1):
        result *= x
    for x in range(2, r + 1):
        result /= x
    return result


result = 0
while True:
    result += conb(n, cnt)
    cnt += 1
    n -= 1
    if cnt > n:
        break
print(int(result))