سُبْحَانَكَ اللَّهُمَّ وَبِحَمْدِكَ، أَشْهَدُ أَنْ لَّا إِلٰهَ إِلَّا أَنْتَ، أَسْتَغْفِرُكَ وَأَتُوبُ إِلَيكَ

How perfect You are O Allāh, and I praise You, I bear witness that none has the right to be worshipped except You, I seek Your forgiveness and turn in repentance to You.

Reference: Al-Nasāʾī in ʿAmal al-Yawm wa al-Laylah (#81, p.\ 173). Also see Irwāʾ al-Ghalīl (3/94).