// editor3
#include<bits/stdc++.h>
using namespace std;
int main()
{
    string w;
    map<int,string>m;
    while(cin>>w)
    {
        if(w.find('-')!=string::npos)
        {
            cout<<"Invalid input";
            return 0;
        }
        for(char c:w)
         if(isdigit(c))
          m[c-'0']+=w.erase(w.find(c).1);
    }
    for(auto&i:m)
     cout<<i.second<<"";
}