use strict;
use warnings;

open my $fh_a, '>', 'input_a.txt' or die "open error: $!";

foreach my $i ( 1 .. 333_333 * 10 ) {
    my $prefix = sprintf('%09s', $i);
    print $fh_a "${prefix}D x\n";
    print $fh_a "${prefix}D y\n";
    print $fh_a "${prefix}E t\n";
}

close $fh_a;