import math


def minmod( alpha: float, beta: float ) -> float:
	"""
	The MinMod operator as defined in [4].
	:param alpha: First operand.
	:param beta: Second operand.
	:return: 0 or first or second operand.
	"""
	absAlpha = math.fabs( alpha )
	absBeta = math.fabs( beta )
	if alpha * beta > 0:
		if absAlpha <= absBeta:
			return alpha
		else:
			return beta
	else:
		return 0