#include <stdio.h>
typedef long long int ll;
int main()
{
  ll N;
  scanf("%lld", &N);

  ll n;
  ll sum = 0;
  int cnt = 0;
  for (n=N; n!=0; n>>=1) {
    cnt++;
    sum += n;
  }

  int i,j;
  ll sum2 = 0;
  ll max = -sum;
  for (i=0; i<cnt; i++) {
    for (n=N,j=0; (n!=0)&&(j<i); n>>=1) {
      sum2 += n;
    }
    sum2 += (n*2);
    if (max < (sum2-sum)) max = sum2-sum;
    sum2 = 0;
  }
  printf("%lld\n", max);
  return 0;
}