#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<iostream>

using namespace std;

char array [1000005];

int main() {
	string s;
	int i, pos;
	char prev;
	bool flag;
	while(cin >> s) {
		//cout << s << endl;
		for (i = 1000004; i >= 0; i--) {
			array[i] = '0';
		}
		for (i = s.length()-1; i >= 0; i--) {
			array[s.length()-1-i] = s[i];
			//printf("char %c\n", s[i]);
		}
		pos = 0;
		if (array[0] == '0') {
			array[0] = '1';
			for (i = s.length()-1; i >= 0; i--) printf("%c", array[i]);
			printf("\n");
		}
		else {
			while(1) {
				//printf("a %c\n", array[pos]);
				prev = array[pos];
				array[pos] = 1 - (array[pos] - '0') + '0';
				if ((pos%2 == 0 && prev == '0') || (pos%2 != 0 && prev == '1')) break;
				pos++; 
			}
			//printf("pos %d\n", pos);
			flag = false;
			for (i = pos; i >= 0; i--) {
				if (array[i] == '1') flag = true;
				if (flag || i == 0) printf("%c", array[i]);
			}
			printf("\n");
		}
	}
	return 0;
}