use strict;
use warnings;

die "No search terms supplied!" unless @ARGV;

my %targets;
my ($prePost) = $ARGV[0] =~ /^(\d+)$/;
my @words = split /(?= )/, do {local $/ = undef; <DATA>};
my @tags;

shift if defined $prePost;
$prePost = 5 unless defined $prePost;
map {$targets{$_} = (0)} @ARGV;

for (0..$#words) {
  $words[$_] =~ s/[\r\n]+/ /;
  my $curr = $words[$_];
  my ($pre, $word, $post) = $curr =~ /([^\w]*)(\w*)(.*)/;
  if (exists $targets{$word}) {
    $words[$_] = "$pre<$word>$post";
    push @tags, $_;
  }

  next if ! @tags or $tags[0] > $_ - $prePost;
  print "".(join '', @words[$tags[0] - $prePost .. $tags[-1] + $prePost])."\n";
  @tags = ();
}

print join '', @words[$tags[0] - $prePost .. $#words] if @tags;