#include <bits/stdc++.h>
using namespace std;
int main() {
	long long int n, max = 0, keep = 0;
	cin >> n;

	for(long long int i = n; 0 < i; i /= 2) {
		if(max < keep + i * 2) max = keep + i * 2;
		keep += i;
		if(i % 2) i--;
	}
	cout << max - keep << endl;

	return 0;
}