Let S = {p1, . . . , ps} be a finite non-empty set of distinct prime numbers, let f ∈ Z[X] be a polynomial of degree n ≥ 1, and let S ′ ⊆ S be the subset of all p ∈ S such that f has a root in Zp. For any non-zero integer y, write y = p k 1 1 . . . p ks s y0, where k1, . . . , ks are non-negative integers and y0 is an integer coprime to p1, . . . , ps. We define the f -normalized S-part of y by [y] f,S := p k 1 r p 1 ,S (f ) 1 . . . p ksr ps,S (f ) s