#include<bits/stdc++.h>
#define int long long
#define endl '\n'
using namespace std;
int x;
signed main(){
	ios::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	cin >> x;
	if(!x)return cout << 0,0;
	cout << (1ll << (64 - __builtin_clzll(x) - __builtin_popcountll(x))) - 1; 
}