How to get date from previous row and add days to it.

[shari]

data temp3;
input @1 grp 1. @5 dt yymmdd10.;
format dt date10.;
datalines;
1 2019-03-11
2 2018-12-15
2 .
2 .
3 2018-12-28
3 .

;

Can someone let me know how to get the missing values populated with previous date+5 days in the particular group.

For example in the group 2,  I want to see the below result.

2    2018-12-15
2    2018-12-20
2    2018-12-25

Thanks in advance!  

[novinosrin · Accepted solution]

data temp3;
infile cards truncover;
input @1 grp 1. @5 dt yymmdd10.;
format dt date10.;
datalines;
1 2019-03-11
2 2018-12-15
2 .
2 .
3 2018-12-28
3 .
;

data want;
set temp3;
by grp;
retain _dt;
if not missing(dt) or first.grp then _dt=dt;
else if missing(dt) then do; dt=_dt+5;_dt=dt;end;
drop _dt;
run;

[shari]

Thank you!