#include <bits/stdc++.h>
using namespace std;

int vf[12];
int main(void){
    //ofstream cout("mincifre.out");
   // ifstream cin("mincifre.in");
    char s;
    while(cin >> s){
        vf[s-'0']++;
    }
    for(int i = 1;i<=9;i++){
        if(vf[i]){
            cout << i;
            vf[i]--;
            break;
        }
    }
    for(int i = 0;i<=9;i++){
        if(vf[i]){
            for(int j = 1;j<=vf[i];j++){
                cout << i;
            }
            vf[i] = 0;
        }
    }
}