n,k,q=map(int,input().split())
a=list(map(int,input().split()))
ans=10**10
for x in a:
  b=[[]]
  can=0
  for i in a:
    if i<x:
      if len(b[-1]):b.append([])
    else:b[-1].append(i)
  if len(b[-1])==0:del b[-1]
  for i in range(len(b)):b[i].sort()
  c=[]
  for i in b:
    i.sort()
    if len(i)>=k:c+=i[:len(i)-k+1]
  if len(c)<q:continue
  ans=min(ans,c[q-1]-c[0])
print(ans)