### 5.6.4 GCD of a list of integers : lgcd

lgcd has a list of integers (or of a list of polynomials)
as argument.

lgcd returns the gcd of all integers of the list (or
the gcd of all polynomials of the list).

Input :

lgcd([18,15,21,36])

Output :

3

Remark

lgcd does not accept two lists (even if they have the same size)
as arguments.