#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pdd = pair<ld, ld>;
using pll = pair<ll, ll>;
using pli = pair<ll, int>;
using pil = pair<int, ll>;
template <typename T>
using Graph = vector<vector<T>>;
const int MOD = 1e9 + 7;
const ld PI = acos(-1);

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N, P;
    ll K;
    cin >> N >> K >> P;
    vector<int> A(N), B(N);
    for (int i = 0; i < N; ++i)
        cin >> A[i];
    for (int i = 0; i < N; ++i)
        cin >> B[i];

    sort(A.begin(), A.end());
    sort(B.begin(), B.end());

    // <= x: >= K
    auto isok = [&](ll x) -> bool {
        ll cnt = 0;
        for (int i = 0; i < N; ++i) {
            if (A[i] < P) {
                cnt += upper_bound(B.begin(), B.end(), x - A[i]) - B.begin();
            }
            cnt += max<int>(upper_bound(B.begin(), B.end(), x - A[i] + P) - lower_bound(B.begin(), B.end(), P - A[i]), 0);
        }
        return cnt >= K;
    };

    ll ok = 1e9, ng = -1;
    while (ok - ng > 1) {
        ll mid = (ok + ng) / 2;
        (isok(mid) ? ok : ng) = mid;
    }

    cout << ok << endl;

    return 0;
}