#include <bits/stdc++.h>
using namespace std;

using ll = long long;

int main()
{
	string s;
	cin >> s;
	ll ans = 0;
	ll cnt = 1;
	for(int i = 0; i < 32; i++) cnt *= 2;
	if(s[0] == 'x')
	{
		for(int i = 1; i < (int)s.size(); i++)
		{
			ans *= 10;
			ans += s[i] - '0';
		}
		ans = cnt - ans;
		cout << ans << endl;
	}
	else cout << s << endl;
	return 0;
}