سُبْحَانَ رَبَّيَ الأَعْلَى (ثلاثا)

How Perfect my Lord is, The Most High. (Three times)

Reference: Abū Dāwud (#871), al-Tirmidhī (#262), al-Nasāʾī (1/190), Ibn Mājah (#888), and Aḥmad (#394, 5/382). Also see Ṣaḥīḥ al-Tirmidhī (1/83).