from bisect import *
from collections import *

N, K, P = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split())) + [10 ** 18]
A.sort(reverse=True)
B.sort()
no = -1
yes = P

def check(m):
    cnt = 0
    Q = deque()
    now = 0
    for a in A:
        while B[now] <= m - a:
            Q.append(B[now])
            now += 1
        while Q:
            if Q[0] < -a:
                Q.popleft()
            else:
                break
        cnt += len(Q)
        
    Q = deque()
    now = 0
    for a in A:
        while B[now] <= m - a + P:
            Q.append(B[now])
            now += 1
        while Q:
            if Q[0] < P - a:
                Q.popleft()
            else:
                break
        cnt += len(Q)
        
    return cnt >= K


while yes - no != 1:
    mid = (yes + no)//2
    if check(mid):
        yes = mid
    else:
        no = mid
print(yes)