Efficiency

Level 1 of the Dungeon
(0, 0, D:1)
  a rat corpse
(41, 20, D:1)
  11 stones

Level 2 of the Dungeon
(0, 0, D:2)
  21 sling bullets
(3, 12, D:2)
  27 stones
(6, 2, D:2)
  a kobold corpse
(8, 2, D:2)
  a stone
(14, 2, D:2)
  4 gold pieces

Level 3 of the Dungeon
(0, 0, D:3)
  15 arrows
(6, -3, D:3)
  19 bolts
(6, -2, D:3)
  a wand of iceblast (9)
(9, -7, D:3)
  a +0 ring mail