#include<iostream>
#include<string>
#include<cctype>
using namespace std;
int main(){
    string str;
    getline(cin, str);
    string result = "";
    for(char c : str){
        if (isdigit(c)){
            cout<<"Invalid input"<<endl;
            return 0;
        }
        if(!isspace(c)){
            result += c;
        }
    }
    cout<,result<<endl;
    return 0;
}