/*
                                    ^....0
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                    ^^     010^   1 1                                   ^^^1110.1
                    0001  10 0   ^ 1.1                                   ^^^1111110
                    0^ 10 . 01   ^^  ^^                                   ^^^1111^1.^           ^^^
                    10  10^ 0^                                             ^^111^^^0.1^       1....^
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        1 1                                                                              0.
        ..                                                                              1 ^
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    ^.0                                                                  001.     .^
    */
//#include <bits/stdc++.h>
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <set>
#include <queue>
#include <map>
const int maxn = 1e6 + 7;
typedef long long ll;
using namespace std;
const ll mod = 998244353;
const long double pi = 3.1415926535897932384626433832795;
map<int, bool> mp;
queue<ll>q;
int main(){
    ll n;
    cin >> n;
    ll ans = 0;
    ll temp = 1;
    while (n){
        n = n / 2;
        ans += temp;
        temp *= 2;
    }
    cout << ans  << endl;
    return 0;
}

Measured memory_bytes: 256