#include<iostream>

#include<vector>

#include<algorithm>

using namespace std;

int main(){

vector<int> d,v;

vector<int>::iterator p1,p2;

int temp,digit,i,pos1,pos2;

while(true){

cin>>digit;

d.clear();

while(digit!=0){

d.push_back(digit%10);

digit/=10;

}

for(i=d.size()-1;i>=0;i--){

if(find(v.begin(),v.end(),d[i])==v.end()) v.push_back(d[i]);

}

for(i=d.size()-1;i>0;i--){

p1=find(v.begin(),v.end(),d[i]);

p2=find(v.begin(),v.end(),d[i-1]);

pos1=p1-v.begin();

pos2=p2-v.begin();

if(pos2<pos1){

temp=v[pos1];

v[pos1]=v[pos2];

v[pos2]=temp;

}

}

for(i=0;i<v.size();i++) cout<<v[i];

cout<<endl;

}

}