#include<bits/stdc++.h>
using namespace std;
using ll = long long;
using vl = vector<ll>;
#define rep(i,n) for(int i=0;i<(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define rep1(i,n) for(int i=1;i<=(n);i++)
#define rrep1(i,n) for(int i=(n);i>0;i--)
#define fore(i_in,a) for (auto& i_in: a)
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define cnts(x,c) count(all(x),c)
#define fio() cin.tie(nullptr);ios::sync_with_stdio(false);
#define DEBUG_CTN(v) cerr<<#v<<":";for(auto itr=v.begin();itr!=v.end();itr++) cerr<<" "<<*itr; cerr<<endl
template<class T> bool chmax(T &a, const T &b) {if (a<b) {a = b; return 1;} return 0;}
template<class T> bool chmin(T &a, const T &b) {if (a>b) {a = b; return 1;} return 0;}
template<class T> void print(const T &t) {cout<<t<<"\n";}
template<class T> void PRINT(const T &t) {rep(i,sz(t)) cout<<t[i]<<" \n"[i==sz(t)-1];}
const ll INF = 1LL << 62;
const int iINF = 1 << 30;

int n;
ll k,p;
vl a,b;

int check(ll x){
    ll cnt=0;
    fore(y,a){
        cnt+=lower_bound(all(b),x-y)-b.begin();
        cnt+=lower_bound(all(b),x+p-y)-lower_bound(all(b),p-y);
    }
    return cnt;
}

int main() {
    fio(); cin>>n>>k>>p;
    a=b=vl(n);
    fore(x,a) cin>>x;
    fore(x,b) cin>>x;
    sort(all(a));sort(all(b));
    ll ng=0,ok=10010010010;
    while(ok-ng>1LL){
        ll mid=(ok+ng)/2;
        if(check(mid)>=k) ok=mid;
        else ng=mid;
    }
    print(ng);
}