def font_size(min, max, high, current_value):
	"""
	calculate font size by min and max occurances
	min - minimum output value
	max - maximum output value
	high - maximum input value
	n - current occurances
	"""
	if max < min:
		raise ValueError('Max cannot be lesser then Min')

	if current_value > high:
		raise ValueError('current_value cannot be greatter then high_value')

	return int((float(current_value) / high) * (max - min) + min)