assign unique ID (Long Value) to each line in RDD

[Ravikant Dindokar]

I have a file containing one line for each edge in the graph with two
vertex ids (source & sink).
sample:
1    2 (here 1 is source and 2 is sink node for the edge)
1    5
2    3
4    2
4    3
I want to assign a unique Id (Long value )to each edge i.e for each line of
the file.

How to ensure assignment of unique value in distributed RDD processing?

Thanks
Ravikant