# ZeroJudge - f384: 次承的痘痘
### 題目連結：https://zerojudge.tw/ShowProblem?problemid=f384
###### tags: `ZeroJudge` `數學`

#include <iostream>
#include <string>
using namespace std;

int main() {
	cin.sync_with_stdio(false); cin.tie(nullptr);
	int number, last;
	string grayCode;
	while (cin >> grayCode) {
		last = number = 0;
		for (int i = 0; i != grayCode.size(); ++i) {
			last = ('0' + last != grayCode[i]);
			number += last << (grayCode.size() - i - 1);
		}
		cout << number << '\n';
	}
}