Efficiency

Level 4 of the Dungeon
(5, -2, D:4)
  8 sling bullets
(11, -1, D:4)
  19 arrows
(17, -8, D:4)
  13 gold pieces

Level 5 of the Dungeon
(0, 0, D:5)
  a scroll of amnesia
(4, -2, D:5)
  a scroll of identify
(6, 15, D:5)
  11 gold pieces

Level 6 of the Dungeon
(0, 0, D:6)
  14 gold pieces