#include <atcoder/all>
#include <iostream>
#include <vector>
#include <algorithm>
#include <set>
using namespace atcoder;
using namespace std;
using ll = long long;
using ull = unsigned long long;
const ull MOD = 1000000007;
using mll = static_modint<1000000007>;
#define rep(i,n) for(int i=0; i<(n); i++)

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

ll cntB(ll bound){
  if(bound >= 0){
    return lower_bound(B.begin(),B.end(),bound) - B.begin();
  }
  return -(ll)(B.end() - lower_bound(B.begin(),B.end(),P+bound));
}

ll cnt(ll k){
  ll res = 0;
  for(ll a : A){
    ll l = 0, r = k + 1;
    l -= a; r -= a;
    res += cntB(r);
    res -= cntB(l);
  }
  return res;
}

int main(){
  cin >> N >> K >> P;
  A.resize(N); rep(i,N) cin >> A[i];
  B.resize(N); rep(i,N) cin >> B[i];
  sort(A.begin(),A.end());
  sort(B.begin(),B.end());

  ll l = 0, r = P;
  while(r-l > 1){
    ll m = (l+r) / 2;
    if(cnt(m-1) < K) l = m; else r = m;
  }
  cout << l << endl;
  return 0;
}

struct ios_do_not_sync{
  ios_do_not_sync(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
  }
} ios_do_not_sync_inst;