#!usr/bin/perl-w
$a="ATCGGCGCCTAT";
code??
print" Letters at 1st position:\n
   A1=$A1; T1=$T1; G1=$G1; C1=$C1; \n
 Letters at 2nd position:\n
  A2=$A2; T2=$T2; G2=$G2; C2=$C2; \n
 Letters at 3rd position:\n
  A3=$A3; T3=$T3; G3=$G3; C3=$C3; \n";
exit;

##</code><code>##

The result of counting from the string should look like:
 Letters at 1st position:
   A1=1; T1=1; G1=2; C1=0; 
 Letters at 2nd position:
   A2=1; T2=1; G2=1; C2=1; 
 Letters at 3rd position:
   A3=0; T3=1; G3=0; C3=3;