calculate seq number within group

[Ronein]

Hello

I want to create serial number within each group by following rule:

Wanted calculate column is called seq.

How can I calculate it please from have data set?

The rule is - for each group we calculate seq numbers but IF values of X,Z are same between rows then rows get same seq number

data have;
input group x z seq;
cards;
111 10 20 1
111 10 20 1
111 30 40 2
222 10 20 1  
222 10 20 1
333 40 50 1
444 15 20 1 
444 15 20 1
444 15 20 1
444 30 50 2
444 60 80 3
444 60 80 3
;
Run;

[Ksharp · Accepted solution]

data have;
input group x z seq;
cards;
111 10 20 1
111 10 20 1
111 30 40 2
222 10 20 1  
222 10 20 1
333 40 50 1
444 15 20 1 
444 15 20 1
444 15 20 1
444 30 50 2
444 60 80 3
444 60 80 3
;
Run;
data want;
 set have;
 by group x z notsorted;
 if first.group then want_seq=0;
 want_seq+first.z;
 run;