def euclideanGCD( a, b ):
    """Calculates the Greatest Common Denominator of two integers using
    the Euclidean algorithm.
    
    Arguments should be integers.
    Returns GCD(a,b)
    
    Note:
        This function will likely hit the recursion limit for big numbers.
    """
    return abs(a) if ( b == 0 ) else euclideanGCD( b, a%b )