Dear Statalisters

I have a dataset looking like the following table
Var1 Var2 Var3
1 3 1
2 5 1
3 1 2
4 6 3
5 2 4
6 4 2










The entries of Var1 and Var2 are "couples", while the range of Var3 is arbitrary set between 1 and 4. I need to create a Var4 where each entry equals the value of Var3 for the corresponding entry of Var2.

My final dataset should therefore look like

Var1 Var2 Var3 Var4
1 3 1 2
2 5 1 4
3 1 2 1
4 6 3 2
5 2 4 1
6 4 2 3
Thanks much in advance for your help, and apologies if a similar question has already been raised on the forum.

Best
MP