#include<iostream>
#include<set>
using namespace std;
int main()
{
    int n;
    while(cin>>n)
    {
        set<int>se;
        int s=n/10;
        int y=n%10;
        int res=0;
        while(s)
        {
            if(se.count(y)==0)
            {
                se.insert(y);
                res=res*10;
                res+=y;
            }
            y=s%10;
            s/=10;
        }
        if(se.count(y)==0)
            {
                se.insert(y);
                res=res*10;
                res+=y;
            }
        cout<<res<<endl;
    }
    return 0;
}