import sequtils, strutils

var a, b, c: int
(a, b, c) = stdin.readLine.split.map parseInt

var list = newSeq[int]()
if b >= c:
  if c mod a == 0:
    list.add c div a
if (c + b) mod a == 0:
  list.add (c + b) div a

if list.len == 0:
  echo -1
  quit()

for v in list:
  echo v