SAS时间序列处理问题

data a;
     input dt 20.;  
datalines;
2006-01-01 12:21:04;
run;
proc format;   
picture dt
low-high='%0d-%b%Y' (datatype=date);
run;
data b;   
length datec10 dtc $20;
     set a;
  datepart=scan(dt,1,' ');
  timepart=scan(dt,2,' ');
  daten=input(datepart,yymmdd10.);
  datec=put(daten,date9.);
  dtc=catx(':',datec,timepart);
     dtn=input(dtc,datetime19.);
  format dtn dt19.;
  keep dt dtn;
  proc print data=b;
run;
程序错误在哪？