#include<iostream>
#include<string>
#include<cctype>
using namespace std;

int main(){
 string text;
 getline(cin, text);
 if(text, length() == 0){
     cout<<"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;
retrun 0;
}