student id	hw1-1	hw1-2	hw1-3
2003-21698	A	90	100
2003-23586	C	50	80
2004-21529	B	70	90
2004-21571	B	70	90
2004-21603	B	70	80
2004-21638	B	90	90
2005-21355	C	70	70
2005-21366	B	70	80
2005-21371	A	100	100
2005-21420	B	40	90
2005-21473	B	70	70
2005-21517	C	0	70
2005-21533	B	85	90
2005-23500	A	70	90
2005-24051	B	100	90
2006-21157	A	65	90
2006-21181	A	85	90
2006-21195	B	100	90
2006-21216	B	30	0
2006-21248	B	70	100
2006-21272	A	70	90
2006-21286	B	0	80