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

int N, P;
long long K;
vector<int> A, B;

long long get_cnt(int x) {
  long long cnt = 0;
  for (auto a : A) {
    auto i = lower_bound(B.begin(), B.end(), P - a) - B.begin();

    // 0 <= E <= x
    int ok = -1, ng = i;

    while (abs(ok - ng) > 1) {
      int mid = (ok + ng) / 2;
      if (a + B[mid] <= x) {
        ok = mid;
      } else {
        ng = mid;
      }
    }

    // P <= E <= P+x
    int ok2 = i - 1, ng2 = N;

    while (abs(ok2 - ng2) > 1) {
      int mid2 = (ok2 + ng2) / 2;
      if (a + B[mid2] <= P + x) {
        ok2 = mid2;
      } else {
        ng2 = mid2;
      }
    }
    cnt += ok + ok2 - i + 2;
  }

  return cnt;
}

int main() {
  cin >> N >> K >> P;
  A.resize(N), B.resize(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 (abs(ok - ng) > 1) {
    int mid = (ok + ng) / 2;
    if (get_cnt(mid) >= K) {
      ok = mid;
    } else {
      ng = mid;
    }
  }

  cout << ok << endl;

  return 0;
}