#include <iostream>
#include <cstdio>
#include <string>
#include <algorithm>
#include <utility>
#include <cmath>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <numeric>
#include <functional>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vector<ll>> vvl;
typedef pair<ll, ll> P;
#define rep(i, n) for(ll i = 0; i < n; i++)
#define exrep(i, a, b) for(ll i = a; i <= b; i++)
#define out(x) cout << x << endl
#define exout(x) printf("%.10f\n", x)
#define chmax(x, y) x = max(x, y)
#define chmin(x, y) x = min(x, y)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define pb push_back
#define re0 return 0
const ll mod = 1000000007;
const ll INF = 1e16;
 
int main() {
    ll n, k, p;
    cin >> n >> k >> p;
    
    vl a(n);
    rep(i, n) {
        cin >> a[i];
    }
    vl b(n);
    rep(i, n) {
        cin >> b[i];
    }
    sort(all(b));
    
    // 判定問題「x以下の数がk個以上あるか？」を二分探索で解く
    ll left = -1;
    ll right = p;
    while(right - left > 1) {
        ll x = (left + right)/2;
        ll cnt = 0;
        rep(i, n) {
            cnt += upper_bound(all(b), x - a[i]) - b.begin();
        }
        if(k <= cnt) {
            right = x;
        }
        else {
            left = x;
        }
    }
    
    out(right);
    re0;
}