from itertools import*
N,K,Q,*A=map(int,open(0).read().split())
l=len
s=sorted
print(min(c[Q-1]-Y for c,Y in zip((s(sum((v[:l(v)-K+1]for v in(s(v)for k,v in groupby(A,lambda a:a>=Y)if k)if l(v)>=K),[]))for Y in A),A)if l(c)>=Q))