What to say upon hearing the Athan (call to prayer) — Du'a 1

يَقُولُ مِثلَ مَا يَقُولُ المُؤَذِّنُ إِلاَّ فِي ((حَيَّ عَلَى الصَّلَاةِ وَحَيَّ عَلَى الفَلَاحِ)) فَيقُولُ: ((لاَ حَولَ وَلاَ قُوَّةَ إِلاَّ بِاللَّهِ)).

English meaning

‘One repeats just as the mu-aththin (one who calls to prayer) says, except when he says: Hayya AAalas-salah (or) hayya AAalal-falah ‘come to prayer, come to success’ instead, one should say: La hawla wala quwwata illa billah. ‘There is no might nor power except with Allah.’