#include<iostream>
#include<vector>
#include<sstream>
#include<stdexcept>

using namespace std;

void validate(string s){
    stringstream ss(s);
    string segment;
    vector<string> groups;
    
    while(getline(ss,segment,'-'))
    
    if(group.size()!=4) throw runtime_error("Invalid");
    
    for(sring g: groups){
        
        if(g,length()!=4) throw runtime_error("Invalid");
        for(char c:g){
            if(!isalnum(c) || islower(c)) throw runtime_error("Invalid");
        }
    }
    cout<<"Valid"<<endl;
}
int main(){
    string input;
    getline(cin,input);
    try{
        validate(input);
    }catch(const exception& e){
        cout<<e.what()<<endl;
    }
    return 0;
}