#include <bits/stdc++.h>
using namespace std;
using ll = long long;

#ifdef LOCAL
#include "debug.hpp"
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...)
#endif

ll N, K, P;
vector<ll> A, B;
bool isOK(ll key) {
  ll cnt = 0;
  for (ll i = 0; i < N; i++) {
    ll a = A[i], temp = 0;
    if (a <= key) {
      ll not_temp = upper_bound(B.begin(), B.end(), P - a - 1) - B.begin();
      ll temp2 = upper_bound(B.begin(), B.end(), key - a) - B.begin();
      temp = N - (not_temp - temp2);
    } else {
      ll not_temp = upper_bound(B.begin(), B.end(), P - a - 1) - B.begin();
      temp = upper_bound(B.begin(), B.end(), key + P - a) - B.begin();
      debug(not_temp, temp);
      temp -= not_temp;
    }
    cnt += temp;
    debug(key, i, temp);
  }
  debug(key, cnt);
  return (cnt >= K);
}

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

  cin >> N >> K >> P;
  A.resize(N);
  B.resize(N);
  for (ll i = 0; i < N; i++) cin >> A[i];
  for (ll i = 0; i < N; i++) cin >> B[i];
  sort(A.begin(), A.end());
  sort(B.begin(), B.end());

  debug(A);

  // m 以下はK個以上ある？
  ll ok = P, ng = -1;
  while (abs(ok - ng) > 1) {
    ll mid = (ok + ng) / 2;
    if (isOK(mid)) ok = mid;
    else ng = mid;
  }
  
  ll ans = ok;
  cout << ans << '\n';
  return 0;
}