Access child elements without knowing the parent

Question

How can i access the circled email and password using android firebase.so far i have tried using the below code but it does not work.

Mref = new Firebase("https://blah blah/");

        Firebase objRef = Mref.child("Administrators");
        objRef.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {
                Map<String, String>map=dataSnapshot.getValue(Map.class);
                String password = map.get("password");
                String email = map.get("email");

                Log.d("email",email);
                Log.d("password",password);

                if(ed1.getText().toString().equals(password)&& ed2.getText().toString().equals(email)){
                    Intent intent=new Intent(Main2Activity.this, MapsActivity.class);
                    startActivity(intent);
                    Log.d("password",password);
                }
                else{
                    Toast.makeText(Main2Activity.this, "Wrong Credentials",Toast.LENGTH_LONG).show();
                }

            }