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

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