pre f = 0:
	A = 0.0


pre f = 1:
	A = 0.0002511999920744595


pre f = 10:
	A = 0.0025119920744966443


pre f = 100:
	A = 0.02511207820801253


pre f = 1000:
	A = 0.24363085080891442


pre f = 10000:
	A = 0.9290876111248088


pre f = 100000:
	A = 0.9992085656008363


pre f = 1000000:
	A = 0.9999920763447353


pre f = 10000000:
	A = 0.999999920762515