while(<>) {
next unless (/\S/);
$block = "";
do {
$_ =~ s/\s+\n$/\n/;
$block .= $_;
} while(($_ = <>) && /\S/);
$block =~ s/\n\./\n\134\&./g;
if ($block =~ /<H2>/) {
$block =~ s/<H2><a[^>]+>([^<]+)<\/a><\/H2>/\n.SH \1\n/g;
$block =~ tr/a-z/A-Z/;
}
$block =~ s/<DT><b><a[^>]+>([^<]+)<\/a>\n(.*)<\/b><\/DT><DD>/\n.SH \1 \2\n/g;
$block =~ s/<[Aa] [Hh][Rr][Ee][Ff]="[^"]+">//g;
$block =~ s/<[Aa] [Nn][Aa][Mm][Ee]="[^"]+">//g;
$block =~ s/<\/[Aa]>//g;
$block =~ s/<\/DD>/\n/g;
$block =~ s/<DL>/\n/g;
$block =~ s/<\/DL>/\n/g;
$block =~ s/\\/\\e/g;
$block =~ s/<b>/\\fB/g;
$block =~ s/<i>/\\fI/g;
$block =~ s/<\/b>/\\fR/g;
$block =~ s/<\/i>/\\fR/g;
$block =~ s/^(<p(re)?>)/.PP\n\1/ if ($wantpp);
$block =~ s/<p> */\n/g;
$block =~ s/ *<\/p>/\n/g;
$block =~ s/<pre>/\n.nf\n.na\n.ft C\n/g;
$block =~ s/<\/pre>/\n.fi\n.ad\n.ft R\n/g;
$block =~ s/<dl[^>]*>/\n/g;
$block =~ s/<ul>/\n/g;
$block =~ s/<\/dl>/\n/g;
$block =~ s/<\/ul>/\n/g;
$block =~ s/<dd>\s*/\n/g;
$block =~ s/<\/dd>/\n/g;
$block =~ s/<li>\s*/\n.IP \\(bu\n/g;
$block =~ s/<dt>\s*/\n.IP "/g;
$block =~ s/\s*<\/dt>/"/g;
$block =~ s/<tt>\s*//g;
$block =~ s/\s*<\/tt>//g;
$block =~ s/<blockquote>/\n.sp\n.in +4\n/g;
$block =~ s/<\/blockquote>/\n.in -4\n/g;
$block =~ s/\n<br>/\n.br\n/g;
$block =~ s/<br>\s*/\n.br\n/g;
$block =~ s/≤/<=/g;
$block =~ s/</</g;
$block =~ s/≥/>=/g;
$block =~ s/>/>/g;
$block =~ s/&/\&/g;
$block =~ s/\s+\n/\n/g;
$block =~ s/^\n//g;
$block =~ s/([a-z][_a-zA-Z0-9-]*)(\([0-9]\))/\\fB\1\\fR\2/g;
print $block;
$wantpp = !($block =~ /^\.(SH|IP)/);
}