#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using VD = vector<double>;
using VVD = vector<VD>;
using VS = vector<string>;
using P = pair<ll,ll>;
using VP = vector<P>;
#define rep(i, n) for (ll i = 0; i < ll(n); i++)
#define out(x) cout << x << endl
#define dout(x) cout << fixed << setprecision(10) << x << endl
#define all(a) (a).begin(),(a).end()
#define rall(a) (a).rbegin(),(a).rend()
#define sz(x) (int)(x.size())
#define re0 return 0
#define pcnt __builtin_popcountll
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
constexpr int inf = 1e9;
constexpr ll INF = 1e18;
//using mint = modint1000000007;
using mint = modint998244353;
int di[4] = {1,0,-1,0};
int dj[4] = {0,1,0,-1};

int main(){
    ll n,k,p;
    cin >> n >> k >> p;
    VL a(n),b(n);
    rep(i,n) cin >> a[i];
    rep(i,n) cin >> b[i];
    sort(all(b));
    b.push_back(INF);
    auto f = [&](ll x){
        ll res = 0;
        rep(i,n){
            auto itr1 = upper_bound(all(b),x-a[i]);
            res += itr1-b.begin();
            auto itr2 = upper_bound(all(b),p-1-a[i]);
            auto itr3 = upper_bound(all(b),p+x-a[i]);
            res += (itr3-b.begin())-(itr2-b.begin());
            //cout << itr1-b.begin() << ' ' << itr2-b.begin() << ' ' << itr3-b.begin() << ' ' << endl;
        }
        return res;
    };
    ll ok = p,ng = -1;
    while(abs(ok-ng) > 1){
        ll mid = (ok+ng)/2;
        //cout << mid << ' ' << f(mid) << endl;
        if(f(mid) >= k) ok = mid;
        else ng = mid; 
    }
    out(ok);
}