from bisect 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
    nowR, nowL = 0, 0
    for a in A:
        while B[nowR] <= m - a:
            nowR += 1
        while nowR - nowL:
            if B[nowL] < -a:
                nowL += 1
            else:
                break
        cnt += nowR - nowL
        
    nowR, nowL = 0, 0
    for a in A:
        while B[nowR] <= m - a + P:
            nowR += 1
        while nowR - nowL:
            if B[nowL] < P - a:
                nowL += 1
            else:
                break
        cnt += nowR - nowL
        
    return cnt >= K


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