use strict;
use warnings;

my $line_count = -1;
my $accum;
while (<STDIN>) {

  # ignore first line of file. It is a header line
  # nonetheless, increment line count
  if ($line_count == -1) {
    print;
    ++$line_count;
    next;
  }

  s!\n!!g;
  
  if ($line_count % 2) { 
    print "$accum$_\n";
    $accum = '';
  } else { 
    $accum = $_;
  }

  ++$line_count;

}