#include <iostream>
#include <string>
#include <unordered_set>
using namespace std;

int main() {
    string s;

    while(cin>>s){
        string res;
        unordered_set<char> record;
        for(char ch:s){
            if(record.count(ch)==0) {
                record.insert(ch);
                res += ch;
            }
        }
        cout<<res<<endl;
    }
    
}
// 64 位输出请用 printf("%lld")