#include <bits/stdc++.h>

using i32 = std::int32_t;
using u32 = std::uint32_t;
using i64 = std::int64_t;
using u64 = std::uint64_t;
using i128 = __int128_t;
using u128 = __uint128_t;
using isize = std::ptrdiff_t;
using usize = std::size_t;

class rep {
    struct Iter {
        usize itr;
        constexpr Iter(const usize pos) noexcept : itr(pos) {}
        constexpr void operator++() noexcept { ++itr; }
        constexpr bool operator!=(const Iter& other) const noexcept { return itr != other.itr; }
        constexpr usize operator*() const noexcept { return itr; }
    };
    const Iter first, last;

  public:
    explicit constexpr rep(const usize first, const usize last) noexcept : first(first), last(std::max(first, last)) {}
    constexpr Iter begin() const noexcept { return first; }
    constexpr Iter end() const noexcept { return last; }
};

template <class T> using Vec = std::vector<T>;

void main_() {
    usize N;
    u64 K;
    u32 P;
    std::cin >> N >> K >> P;
    Vec<u32> A(N), B(N);
    for (auto& x : A) {
        std::cin >> x;
    }
    for (auto& x : B) {
        std::cin >> x;
    }
    std::sort(A.begin(), A.end());
    std::sort(B.begin(), B.end());
    // それ未満が K 個未満
    u32 ok = 0, ng = P;
    while (ng - ok > 1) {
        const auto md = (ok + ng) / 2;
        u64 cnt = 0;
        usize a = N, b = N, c = N;
        for (const auto x : A) {
            // x + y < P のとき
            // x + y < md <=> y < md - x
            // x + y >= P のとき
            // P <= x + y < P + md <=> P - x <= y < P - x + md
            if (x <= md) {
                while (a > 0 and B[a - 1] >= md - x) {
                    a -= 1;
                }
                cnt += a;
            }
            while (b > 0 and B[b - 1] >= P - x + md) {
                b -= 1;
            }
            while (c > 0 and B[c - 1] >= P - x) {
                c -= 1;
            }
            cnt += b - c;
        }
        if (cnt < K) {
            ok = md;
        } else {
            ng = md;
        }
    }
    std::cout << ok << '\n';
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);
    main_();
    return 0;
}