from bisect import*
n, k, p = map(int, input().split())
A = tuple(map(int, input().split()))
B = sorted(map(int, input().split()))
def test(x):
    cnt = 0
    for a in A:
        cnt += bisect_right(B, x-a)
        cnt += bisect_right(B, p+x-a) - bisect_right(B, p-a-1)
    return cnt >= k
ok = p
ng = -1
while ok - ng > 1:
    mid = (ok + ng) // 2
    if test(mid):
        ok = mid
    else:
        ng = mid
print(ok)