Is Surat Al-Fatihah and another surah recited, or just Surat Al-Fatihah, in the two rak'ahs of Tahiyat Al-Masjid (greeting the mosque prayer)?

It is sunnah for one who enters the mosque to pray two rak'ahs before sitting, based on the Prophet's (peace and blessings be upon him) saying: "When any of you enters the mosque, let him not sit until he prays two rak'ahs." These two rak'ahs are a sunnah, not obligatory. It is recommended to recite Al-Fatihah and another surah after it, and the prayer is valid by only reciting Al-Fatihah.