// editor1
#include<iostream>
#include<regex<
using namespace std;
int main() {
    string a;
    cin>>a;
    regex pattern("^[A-Z0-9]{4}-[4-Z0-9]{4}-[A-Z0-9]{4}$");
    if(regex_match(a,pattern)){
        cout<<"valid";
    }else{
        cout<<"Invalid";
    }
}