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

int main() {
    string username;
    int age;
    cout << "Enter username: ";
    cin >> username;
    cout << " ENter age: ";
    cin >> age;
    
    if (username.length() <3) {
        cout << "\mathbf{Invalid\ username}" << endl;
    }
    else if (age < 18 || age >100){
        cout << "\mathbf{Invalid\ age}" << endl;
    }
    else{
        cout << "\Registration\ is \ successful}" << endl;
    }
    return 0;
}