#include<iostream>
#include<string>
using namespace std;
int main()
{
    string input,cleaned;
    getline(cin,input);
    for(char ch:input)
    {
        if(ch=='-')
        {
            cout<<"Invalid input";
             return 0;
        }
         for(char ch:input)
         {
        if(isalnum (ch)){
         cleaned+=ch;
        }}
    }
    cout<< cleaned+=ch;
    return 0;
}