Need to get common users to multiple users mapped to it

Hadoop
N/A

Need to get common users to multiple users mapped to it

Hi,

I have a table which has one user ID mapped to multiple user IDs. I want to get the common user IDs mapped to each of the two user IDs

My Data looks in the following way

User ID User ID 1
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
2 1
2 3
2 5
2 7
2 9
2 11
2 13
2 15
2 17
. .
. .
. .
. .
. .
. .
2000
2001

I need to get for every User ID combination starting from (1,2) till (1999,2000) how many common User ID1's are there

Thanks in advance for any solution