data t1;
length x 8;
infile cards;

input @'a' x 1. @; output;
input @'b' x 1. @; output;
input @'c' x 1. @; output;

cards;
a1b2c3d4
;

proc print;run;

data t1;
length x 8;
infile cards;
input @'a' x 1. @@; output;
cards;
a1a2a3a4
;
proc print;run;