#include "bits/stdc++.h"
#include "atcoder/all"
using namespace std;
using namespace atcoder;
using mint = modint1000000007;
const int mod = 1000000007;
//using mint = modint998244353;
//const int mod = 998244353;
//const int INF = 1e9;
//const long long LINF = 1e18;
//const bool debug = false;
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define rep2(i,l,r)for(int i=(l);i<(r);++i)
#define rrep(i, n) for (int i = (n-1); i >= 0; --i)
#define rrep2(i,l,r)for(int i=(r-1);i>=(l);--i)
#define all(x) (x).begin(),(x).end()
#define allR(x) (x).rbegin(),(x).rend()
#define endl "\n"
#define P pair<mint,mint>
template<typename A, typename B> inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; }
template<typename A, typename B> inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; }
vector<int>a, b;
bool f(int x, long long k, int p) {
	long long c = 0;
	long long c0 = 0;
	long long c1 = 0;
	//[0,x]
	rep(i, a.size()) {
		c0 += upper_bound(all(b), x - a[i]) - lower_bound(all(b), 0 - a[i]);
	}
	//[p,x+p]
	rep(i, a.size()) {
		c1 += upper_bound(all(b), (x + p) - a[i]) - lower_bound(all(b), p - a[i]);
	}
	c = c0 + c1;
	// cout << x << " " << c0 << " " << c1 << endl;
	return c >= k;
}
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	int n; long long k; int p;
	cin >> n >> k >> p;
	a.resize(n);
	b.resize(n);
	rep(i, n)cin >> a[i];
	rep(i, n)cin >> b[i];
	sort(all(a));
	sort(all(b));
	int ng = -1;
	int ok = p - 1;
	while (1 < abs(ok - ng)) {
		long long c = (ng + ok) / 2;
		if (f(c, k, p)) ok = c;
		else ng = c;
	}
	cout << ok << endl;
	return 0;
}