use warnings;
use strict;

gf ();
gf ();

sub gf
{
    my $ins1 = '4 A -4 C -4 B 1 D';
    our @inserts = ();
    $ins1 =~ /[\d+-]+(?: \w ([\d+-]+)(?{push @inserts, $1}))*/g;
    print "\n" . join ' ', @inserts;
}