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

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