#include <bits/stdc++.h>
using namespace std;
#define rep(i, n) for(int i = 0; i < n; i++)
#define rep2(i, x, n) for(int i = x; i <= n; i++)
#define rep3(i, x, n) for(int i = x; i >= n; i--)
#define each(e, v) for(auto &e: v)
#define pb push_back
#define eb emplace_back
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)x.size()
using ll = long long;
using pii = pair<int, int>;
using pil = pair<int, ll>;
using pli = pair<ll, int>;
using pll = pair<ll, ll>;
const int MOD = 1000000007;
//const int MOD = 998244353;
const int inf = (1<<30)-1;
const ll INF = (1LL<<60)-1;
template<typename T> bool chmax(T &x, const T &y) {return (x < y)? (x = y, true) : false;};
template<typename T> bool chmin(T &x, const T &y) {return (x > y)? (x = y, true) : false;};

struct io_setup{
    io_setup(){
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout << fixed << setprecision(15);
    }
} io_setup;

int main(){
    ll N, K, P; cin >> N >> K >> P;

    vector<ll> c(P+1, 0);
    vector<ll> A(N), B(N);
    rep(i, N) cin >> A[i];
    rep(i, N) cin >> B[i];

    rep(i, N){
        c[B[i]+1]++;
    }

    rep(i, P){
        c[i+1] += c[i];
    }

    ll L = -1, R = P; //(L, R]
    //rep(i, P+1) cout << c[i] << ' '; cout << '\n';

    while(R-L > 1){
        ll M = (L+R)/2;

        ll C = 0;
        
        rep(i, N){
            C += c[max(M-A[i]+1, 0LL)];
            C += c[min(P, P+M-A[i]+1)]-c[P-A[i]];
        }

        //cout << M << ' ' << C << '\n';

        if(C >= K) R = M;
        else L = M;
    }

    cout << R << '\n';
}