### 5.8.6 Simplification of a pair of integers : simp2

simp2 takes as argument two integers or a list of two integers
which represent a fraction (for two polynomials see 5.31.6).

simp2 returns the list of the numerator and the denominator of
an irreducible representation of this fraction
(i.e. after simplification).

Input :

simp2(18,15)

Output :

[6,5]

Input :

simp2([42,12])

Output :

[7,2]