#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define rep(i,n) for(int (i)=0;(i)<(n);(i)++)
#define Pr pair<ll,ll>
#define Tp tuple<ll,ll,ll>
using Graph = vector<vector<int>>;

ll mod = 1000000007;


//mod逆元
long long modinv(long long a, long long m) {
    long long b = m, u = 1, v = 0;
    while (b) {
        long long t = a / b;
        a -= t * b; swap(a, b);
        u -= t * v; swap(u, v);
    }
    u %= m;
    if (u < 0) u += m;
    return u;
}
 
 
//Combination2
//10^6くらいまで
//modはグローバルに定義しておく
vector<ll> fact;
vector<ll> invf;
ll comb(ll n,ll k){
    if(n<0||k<0||k>n) return 0LL;
    else{
        ll a = fact[n]*invf[k]%mod;
        a = a*invf[n-k]%mod;
        return a;
    }
}
    /*
    //main関数内に以下ペースト
    //N:max
    fact.assign(2*N+1,1LL);
    invf.assign(2*N+1,1LL);
    rep(i,2*N) fact[i+1] = fact[i]*(i+1)%mod;
    rep(i,2*N+1) invf[i] = modinv(fact[i],mod);
    */

int main() {
    ll N,K,P; cin >> N >> K >> P;
    ll a[N]; vector<ll> b;
    rep(i,N) cin >> a[i];
    rep(i,N){
        ll d; cin >> d;
        b.push_back(d);
    }
    sort(b.begin(),b.end());
    //解から二分探索 binary search
    //分かれ目の"r"側の値を求める
    ll l,r,ans;
    l = 0; r = P; //初期値の代入
    while(l<r){
        ll c = (l+r)/2;
        //cの場合に検証
        ll cnt = 0;
        rep(i,N){
            cnt -= lower_bound(b.begin(),b.end(),0LL)-b.begin();
            cnt += lower_bound(b.begin(),b.end(),c-a[i]+1)-b.begin();
            cnt -= lower_bound(b.begin(),b.end(),P-a[i])-b.begin();
            cnt += lower_bound(b.begin(),b.end(),P+c-a[i]+1)-b.begin();
        }
        if(cnt<K){//cが"l側"になる条件判定
            l = c+1;
        }
        else r = c;
    }
    ans = l;
    cout << ans << endl;
}