Sequence

[RK]

Hi,
How can I get sequence no in column C using A and B without concatenating both A and B which are numeric variables? Thanks so much.

A B C
1 2 1
1 2 1
1 3 2
1 3 2
1 4 3
1 5 4
1 6 5
2 1 6
2 1 6
2 1 6
2 2 7
2 2 7
2 2 7
2 2 7
3 4 8
3 5 9
3 6 10
3 6 10
3 6 10
3 7 11
3 7 11
3 7 11

[Ksharp]

data want;
 set have;
 by A B notsorted;
 C+first.B;
run;