# -*- coding: utf-8 -*-

N = int(input())

fames = []
fame = N
while fame > 0:
    fames.append(fame)
    fame //= 2
suffix_sums = [0]*len(fames)
fame_sum = 0
for i in range(len(fames)-1, -1, -1):
    fame_sum += fames[i]
    suffix_sums[i] = fame_sum
max_fame = -1
for i in range(len(fames)-1, -1, -1):
    max_fame = max(suffix_sums[0] - suffix_sums[i] + fames[i]*2, max_fame)

print(max_fame - suffix_sums[0])