I was going through the number theory text by Ireland and Rosen, and was following the proof of the divergence of the sum of reciprocal primes. But I came across a step unclear to me.
The proof so far: https://imgur.com/XbPkBak&JeMOqku
The step itself: https://imgur.com/XbPkBak&JeMOqku#1
I cannot see the equality between the two sides. Help is appreciated.