#include<iostream>
#include<string>
using namespace std;
int main(){
    string str;
    getline(cin,str);
    if(str.length()==0){
        cout<<"Invalid input";
        return 0;
    }
    string result="";
    for(char ch:str){
        if(ch>='o'&& ch<='9'){
            cout<<"Invalid input";
            return 0;
        }
    }    
    string result="";
    if(ch !=' '){
        result +=ch;
    }
    
    cout<< result;
    return 0 ;
    
}