#include <bits/stdc++.h>
using namespace std;
int main(){
    string str;
    cin >> str;
    int n=str.length();
    int cnt0=0,cnt1=0;
    for (int i=0;i<n;i++){
        if (str[i]=='0') cnt0++;
        else cnt1++;
    }
    if (cnt0==n){
        cout << "0" << "\n";
        return 0;
    }
    if (cnt1==n){
        cout << "1" << "\n";
        return 0;
    }
    if (str.front() != str.back()){
        cout << str.front() << str.back() << "\n";
        return 0;
    }
    cout << str.back() << (char)('1'+'0'-str.back()) << str.back() << "\n";
    return 0;
}