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

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