#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define srep(i, s, t) for (int i = s; i < t; ++i)
#define drep(i, n) for (int i = (n)-1; i >= 0; --i)
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
#define MAX_N 10000005

int bb[MAX_N];

int main() {
    ll n, K, P;
    cin >> n >> K >> P;
    int a[n] = {};
    rep(i, n) cin >> a[i];
    rep(i, n) {
        int b;
        cin >> b;
        bb[b]++;
    }
    srep(i, 1, MAX_N) { bb[i] += bb[i - 1]; }

    int l = 0, r = P;

    while (l + 1 < r) {
        int m  = (l + r) / 2;
        ll cnt = 0;
        // m以上の数を数える
        rep(i, n) {
            if (a[i] < m) {
                int mi = m - a[i];
                int ma = P - 1 - a[i];
                cnt += bb[ma];
                if (mi > 0) cnt -= bb[mi - 1];
            } else {
                int ma = P - 1 - a[i];
                cnt += bb[ma];
                int mi = P - (a[i] - m);
                if (mi < P) { cnt += bb[P - 1] - bb[mi - 1]; }
            }
        }
        // cout << m << ' ' << cnt << endl;
        if (n * n - cnt >= K) r = m;
        else
            l = m;
    }

    cout << l << endl;
    return 0;
}