#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < (n); i++)
using namespace std;
typedef long long ll;

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);

    vector<ll> v;
    ll N; cin >> N;
    ll sum = 0;
    while(N > 0){
        v.emplace_back(N);
        sum += N;
        N /= 2;
    }
    ll s = v[0] * 2;
    ll ma = s - sum;
    rep(i,v.size()-1){
        s += 2 * v[i+1] - v[i];
        ma = max(ma, s - sum);
    }
    cout << ma << endl;
}