#include<iostream>
using namespace std;
int main()
{
    string name;
    int age;
    cin>>name;
    cin>>age;
    if(name.length()<=3){
        cout<<"Invalid username";
        
    }
    else if(18<age){
    cout<<"invalid username";
    }
    else if(100>age)
        cout<<"invalid username"
    
    else
    {
        cout<<"Registration successful";
    }
    return 0;
}