请教各位这个程序怎么编

data m;
format cust_id $18. birth date9.;
input cust_id $18.;
birth=input(prxchange('s/\d{6}(\d{8})/$1/', 1, cust_id),yymmdd8.);
year=yrdif(birth,today(),'ACTUAL');
cards;
150422193810130044
;
run;