#include <bits/stdc++.h>

using namespace std;

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	int red = 0, blue = 0;
	string S;
	cin >> S;
	for (int i = 0; i < S.size(); ++i){
		if (S[i] == '0') red++;
		else blue++;
	}
	cout << S - 2*min(red,blue) << '\n';
	cout << flush;
	//for (int i = 0; i < 1e9; ++i){for (int j = 0; j < 1e9; ++j){}}
	
}