#include<iostream>
#include<string>
#include<cctype>

int main(){
    string text;
    getline(cin,text);
    if(text.length() == 0){
        count<<"Invalid  input";
        return 0;
    }
    for(char ch : text){
        if(isdigit(ch)){
            cout<<"Invalid input";
            return 0;
        }
    
        
 }
    
string result="";
for(char ch:text){
    if(ch !=' '){
        result +=ch;
        
    }
}
cout<<result;
return 0;
}