#include <stdio.h>
#include <iostream>
#include <vector>
#include <queue>
#include <stack>
#include <algorithm>

using ll = long long int;
const int INF = (1<<30);
const ll INFLL = (1ll<<60);
const ll MOD = (ll)(1e9+7);

#define l_ength size

void mul_mod(ll& a, ll b){
	a *= b;
	a %= MOD;
}

void add_mod(ll& a, ll b){
	a = (a<MOD)?a:(a-MOD);
	b = (b<MOD)?b:(b-MOD);
	a += b;
	a = (a<MOD)?a:(a-MOD);
}

int n;
ll k,p,a[100100],b[100100];

bool check(ll x){
	int i;
	ll cnt=0ll;
	for(i=0; i<n; ++i){
		cnt += (ll)(std::lower_bound(b,b+n,x-a[i])-std::lower_bound(b,b+n,0ll-a[i]));
		cnt += (ll)(std::lower_bound(b,b+n,p+x-a[i])-std::lower_bound(b,b+n,p-a[i]));
	}
	return (cnt<k);
}

int main(void){
	int i;
	ll ok=0ll,ng,mid;
	std::cin >> n >> k >> p; ng = p;
	for(i=0; i<n; ++i){
		std::cin >> a[i];
	}
	for(i=0; i<n; ++i){
		std::cin >> b[i];
	}
	std::sort(b,b+n);
	while(ng-ok>1ll){
		mid = (ok+ng)/2;
		if(check(mid)){
			ok = mid;
		}else{
			ng = mid;
		}
	}
	std::cout << ok << std::endl;
	return 0;
}