from bisect import bisect_left, bisect_right

N, K, P = map(int, input().split())
As = sorted(map(int, input().split()))
Bs = sorted(map(int, input().split()))

def isok(m):
    cnt = 0
    p = N
    q = N
    r = N
    for A in As:
        while p > 0 and m - A < Bs[p - 1]:
            p -= 1
        while q > 0 and m - A + P < Bs[q - 1]:
            q -= 1
        while r > 0 and - A + P <= Bs[r - 1]:
            r -= 1
        cnt += p + q - r
    # print(m ,cnt)
    return cnt < K


ok = -1
ng = P
while ng - ok > 1:
    mid = (ok + ng) // 2
    if isok(mid):
        ok = mid
    else:
        ng = mid

print(ok + 1)