#include <bits/stdc++.h>

using namespace std;
void fast_io() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
}

int main() {
    fast_io();
    int n, p;
    long long 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(b.begin(), b.end());
    int ng = -1, ok = p;
    while (ok - ng > 1) {
        int mid = (ok + ng) / 2;
        long long cnt = 0;
        for (int ai : a) {
            // ai + bj <= mid
            auto it = lower_bound(b.begin(), b.end(), mid - ai + 1);
            cnt += it - b.begin();
            // p <= ai + bj <= p + mid
            auto it_1 = lower_bound(b.begin(), b.end(), p + mid - ai + 1);
            auto it_2 = lower_bound(b.begin(), b.end(), p - ai);
            cnt += it_1 - it_2;
        }
        if (cnt >= k) {
            ok = mid;
        } else {
            ng = mid;
        }
    }
    cout << ok << endl;
}