while(/(.)/g) {
my $letter= uc $1;
print $letter;
my $len=length($letter);

my $sub="";
if ($letter=="A") { $sub="T";}
elsif ($letter=="T") { $sub="A";}
elsif ($letter=="G") { $sub="C";}
elsif ($letter=="C") { $sub="G";}
print "  $len\t$sub\n"; 
} # close while

##</code><code>##

A  1	T
A  1	T
G  1	T
C  1	T
T  1	T
T  1	T