open my $f,"<gen_machines_data.txt" or die $!;
my($slots_used,$slots_free);
while(<$f>)
{
#print $_;
$slots_used += (split(/\s+/,$_))[3];
$slots_free++;
}
close $f;
print "total slots used:$slots_used\n";
print "total slots free:$slots_free\n";