#include <iostream>
#include <string>

int main(){
    string text;
    getline(cin, text);
        if(text.length() == 0){
            cout<<"Invalid input";
            return 0;
        }
        string result = "";
        for(int i=0; i<text.length();i++){
            char ch = text[i];
            if(ch>='0' && ch<='9'){
                cout<<"Invalid input";
                return 0;
            }
            if(ch !=''){
                result += ch;
            }
        }
        cout<<result;
    return 0;
}