Class1	Class2	CLass3	Freq
S1	S2	S2	1
S1	S2	S1	3
S1	S3	S2	2
S1	S1	S1	3
S1	S1	S3	1
S2	S1	S1	2
S2	S1	S2	2
S2	S3	S3	1
S2	S2	S2	1