#include<iostream>
#include<regex>
using namespace std;
int main(){
    string s;
    cin>>s;
    regex pattern("^[A-Z0-9]{4}(-[A-Z0-9]{4}{3}$");
    if(regex_match(s,pattern))
      if(isdigit(s) && isalpha(s)){
        cout<<"Valid";
      }   
    else{
        cout<<"Invalid";
    }
    return 0;
}