#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using pll = pair<ll, ll>;
using tlll = tuple<ll, ll, ll>;
constexpr ll MOD = 1e9 + 7;
//constexpr ll MOD = 998244353;
//constexpr ll MOD = ;
ll mod(ll A, ll M) {return (A % M + M) % M;}
constexpr ll INF = 1LL << 60;
template<class T> bool chmin(T& a, T b) {if (a > b) {a = b; return true;} return false;}
template<class T> bool chmax(T& a, T b) {if (a < b) {a = b; return true;} return false;}
ll divceil(ll A, ll B) {return (A + (B - 1)) / B;}
#define FINALANS(A) do {cout << (A) << '\n'; exit(0);} while (false)

ll N, K, P;
vector<ll> A, B, S;

void accum(vector<ll> &s)
{
  s.resize(2 * P, 0);
  for (ll i = 0; i < N; i++)
  {
    s.at(A.at(i))++;
    s.at(P + A.at(i))++;
  }

  /*
  for (ll i = 0; i < 2 * P; i++)
  {
    cerr << i << " " << s.at(i) << endl;
  }
  //*/

  for (ll i = 0; i < 2 * P - 1; i++)
  {
    s.at(i + 1) += s.at(i);
  }
}

ll count(ll t)
{
  ll ret = 0;
  for (ll i = 0; i < N; i++)
  {
    ll tmp = S.at(P + t - B.at(i)) - S.at(P - B.at(i) - 1);
    ret += tmp;
  }
  return ret;
}

bool isok(ll t)
{
  return count(t) >= K;
}

int main()
{
  cin >> N >> K >> P;
  A.resize(N), B.resize(N);
  for (ll i = 0; i < N; i++)
  {
    cin >> A.at(i);
  }
  for (ll i = 0; i < N; i++)
  {
    cin >> B.at(i);
  }

  accum(S);

  /*
  for (ll i = 0; i < 2 * P; i++)
  {
    cerr << i << " " << S.at(i) << endl;
  }
  //*/

  ll ng = -1, ok = P - 1;
  while (abs(ok - ng) > 1)
  {
    ll mid = (ok + ng) / 2;
    if (isok(mid))
      ok = mid;
    else
      ng = mid;
  }
  cout << ok << endl;

  /*
  for (ll p = 0; p < P; p++)
  {
    cerr << count(p) << endl;
  }
  //*/
}