public class Employee
{
	private int employeeId;
	public Employee()
	{
		this.employeeId = Employer.getId();
	}

    public int getEmployeeId() {
        return employeeId;
    }
}


import java.util.HashMap;
class Employer
{
	private static HashMap<Integer,Employee> employees;
	public Employer()
	{
		employees =  new HashMap<Integer,Employee>();
	}
	public void addEmployee()
	{
		employees.put(employees.size(),new Employee());
	}

    public static Integer getId()
	{
		return 100+employees.size();
	}
}