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


int main(){
    
    string str;
    while(cin>>str){
        //计数
        int counts[26]={0};
        for(int i=0;i<str.size();++i){
            counts[int(str[i]-'a')]++;
        }
        //选最小
        int min=100000;
        set<char> s;
        for(int i=0;i<26;++i){
            if(counts[i]<=min&&counts[i]>=1)
                min = counts[i];
        }
        for(int i=0;i<26;++i){
            if(counts[i]==min)
                s.insert('a'+i);
        }
        string res="";
        for(int i=0;i<str.size();++i){
            if(s.find(str[i])==s.end())
                res.push_back(str[i]);
        }
        cout<<res<<endl;
    }
    return 0;
}