my $amount = shift; # disperse amount
die "must be integer" if $amount != int($amount);
die "too big" if $amount > 1000;
die "too small" if $amount < 1;
for (my $en = 1; $amount; $en <<= 1) {
  next unless $amount & $en;
  print "Giving you envelope with $en\n";
  $amount &= ~ $en;
}