n, k, q = map(int, input().split())
alist = list(map(int, input().split()))
ans = None
for i, a in enumerate(alist):
  spla = []
  preva = -1
  ailist = alist[:i] + alist[i+1:]
  for j, _a in enumerate(ailist):
    if _a < a:
      spla.append(ailist[preva+1:j])
      preva = j
  if not preva == len(ailist)-1:
    spla.append(ailist[preva+1:])
  conda = []
  for sa in spla:
    if len(sa) >= k:
      conda.extend(list(sorted(sa))[:len(sa)-k+1])
  if len(conda) < q-1:
    continue
  else:
    y = list(sorted(conda))[q-2]
    if ans is None or ans > y - a:
      ans = y - a

print(ans)
