Fifty (50) Namaaz
There’s no such thing as authentic (as in it can be attributed to the prophet SAW with certainty) in the matters of of hadith. Sahih is a terminology in hadith science, which means that a muhadith has verified a hadith chain satisfactorily according to his principles. A hadith that is graded as sahih by one muhadith might not be acceptable by another due to certain issues in the chain that he found. Even if a hadith is accepted by all muhadithin, it’s content will still be judged in the light of the Quran.