Do four rak'ahs after 'Isha' count as observing Laylat al-Qadr, or does praying Maghrib and 'Isha' in congregation on Laylat al-Qadr count as observing the entire Laylat al-Qadr?

Praying four connected rak'ahs after 'Isha' is equivalent in reward to observing the Night of Decree (Laylat al-Qadr), as was authentically reported from some Companions like Ibn Mas'ud. This is a great virtue, yet it does not replace the virtue of the Night of Decree itself in the forgiveness of sins. And whoever prays 'Isha' and Fajr in congregation on the Night of Decree, it is as if he stood in prayer the entire night. This is a great virtue. What is more important is to increase in acts of worship during the last ten nights, for the Night of Decree is better than a thousand months.