#include <iostream>
#include <string>

using namespace std;

class LoginException{
	private:
		string login;
	public:
		LoginException(string u=""):login(u){}
		string getLogin() const {return login;}
};

int main(){
	string uname, pwd;
	cout << "User => ";
	cin >> uname;

	cout << "Password => ";
	cin >> pwd;

	try{
		if ( uname.compare("abc")==0 && pwd.compare("abc")==0){
			cout << "Login ok..." << endl;
		}
		else throw LoginException(uname);
	}
	catch (LoginException e) {
		cout << "Invalid username or password: username=" << e.getLogin()  << endl;
	}
	catch (...){
		cout  << "Unknown error has occured" << endl;
	}

	return 0;
}