  For a prime $p$, the OM algorithm finds the $p$-adic factorization of an
irreducible polynomial $f\in\mathbb{Z}[x]$ in polynomial time. This may be
applied to construct $p$-integral bases in the number field $K$ defined by $f$.
In this paper, we adapt the OM techniques to work with a positive integer $N$
instead of $p$. As an application, we obtain an algorithm to compute global
integral bases in $K$, which does not require a previous factorization of the
discriminant of $f$.

Number Theory