#include "bits/stdc++.h"
#define int long long

using namespace std;
using ll = long long;
using P = pair<ll, ll>;
const ll INF = (1LL << 61);
ll mod = 1000000007;

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	int N, K, P; cin >> N >> K >> P;
	vector<int>A(N);
	for (int i = 0; i < N; i++)cin >> A[i];
	vector<int>tmp(P);
	for (int i = 0; i < N; i++) {
		int B; cin >> B;
		tmp[B]++;
	}
	vector<int>sum(P + 1);
	for (int i = 0; i < P; i++)sum[i + 1] = sum[i] + tmp[i];
	int l = -1, r = P;
	while (r - l > 1) {
		int mid = (l + r) / 2;
		int cnt = 0;
		for (int i = 0; i < N; i++) {
			if (A[i] <= mid) {
				cnt += sum[mid - A[i] + 1];
			}
			cnt += sum[min(P, P + mid - A[i])] - sum[P - A[i] - 1];
			
		}
		if (cnt >= K)r = mid;
		else l = mid;
	}
	cout << r << endl;
	return 0;


}