import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()
# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = 10**16
# md = 998244353
md = 10**9+7

n, k, p = LI()
k -= 1
aa = LI()
bb = LI()
aa.sort()
bb.sort()

# mより小さい数を数える
def cnt(m):
    res = 0
    i = n-1
    for a in aa:
        while i >= 0 and a+bb[i] >= m:
            i -= 1
        if i < 0: break
        res += i+1
    return res

l, r = 0, p
while l+1 < r:
    m = (l+r)//2
    if cnt(m)-cnt(p)+cnt(m+p) > k: r = m
    else: l = m

print(l)