n, k, p = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))

A.sort()
B.sort()

import bisect
def is_ok(x):
    cnt = 0
    for a in A:
        cnt += bisect.bisect_right(B, x-a)
        cnt += bisect.bisect_right(B, p+x-a)-bisect.bisect_left(B, p-a)
    return cnt >= k

ng = -1
ok = p
while ng+1 < ok:
    c = (ng+ok)//2
    if is_ok(c):
        ok = c
    else:
        ng = c
print(ok)