#include <bits/stdc++.h>
#define ll long long
#define MOD 997
using namespace std;
ifstream fin("ordine.in");
ofstream fout("ordine.out");
string s;
int fv[130];

int main() {
    fin >> s;
    int l = s.size();
    for (int i = 0; i < s.size(); ++i)
        ++fv[s[i]];
    s = " ";
    while (l--) {
        for (int i = 'a'; i <= 'z'; ++i)
            if (fv[i] > 0 && i != s[s.size() - 1]) {
                s += i;
                --fv[i];
                break;
            }
    }
    s.erase(0, 1);
    fout << s;
    return 0;
}