n = int(input())

digit = 0
L = []
while n != 0:
    if n % 2 == 1:
        L.append(digit)
    n //= 2
    digit += 1
m = len(L)
mid = pow(2, m - 1)
i = 0
ans = 0
while mid != 0:
    if mid % 2 == 1:
        ans += pow(2, L[i])
    mid //= 2
    i += 1
print(ans)