#include<iostream>
#include<string>
using namespace std;
int main(){
    string s;
    getline(cin,s);
    string result ="";
    for (char c:s){
        if(isdigit(c)){
            count<<"invalid input";
            return 0;
        }
        if(c!=' ')
        result+=c;
    }
    cout<<result;
    return 0;
}