n, k, q = map(int, input().split())
a = [(int(x), i) for i, x in enumerate(input().split())]
a.sort()
m = a[q - 1][0] - a[0][0]
v = []
for i in range(1, n - q + 1):
    mi = a[q - 1 + i][0] - a[i][0]
    bis = list(range(i))
    for ai in range(i, i + q):
        ok = True
        for bi in bis:
            if abs(a[bi][1] - a[ai][1]) < k:
                bis.append(ai)
                ok = False
                con = False
                if i + q < n:
                    mi = a[q + i][0] - a[i][0]
                    if mi < m:
                        con = True
                break
        if con: continue
        break
    if ok:
        m = mi
print(m)
