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		The figure shows a triangle ABC with the 
		circumcircle O. D is any point and E is a point on the circumcircle O. 
		Lines AD, BD, and CD meet the circumcircle O at A', B', and C', 
		respectively. Lines EA', EB', and EC' meet lines BC, AC, and AB at A", 
		B", and C", respectively. Prove that points A", B", C", and D are 
		collinear. 
				 
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