count duplicate entries

[jamal sasha]

Hi,
 I have data in hdfs like:

id1,field1,field2
1,2,3
1,2,3
1,2,4
1,2,5
I want to find the number of unique entries using pig..
So here, number of unique entries are 3 ( as 1,2,3 is repeated twice)

How do i find this?

Thanks