#include<bits/stdc++.h>
namespace rgs = std::ranges;
using std::cin, std::cout;
using ll = long long;
using u64 = unsigned long long;
using db = double;
const int N = 50005;
int n, k;
ll a[N], b[N], c[N];
void init(ll * a) {
	for(int i = 1;i <= n;++i) {
		cin >> a[i];
	}
	std::sort(a + 1, a + n);
	a[n + 1] = 1e10;
}
ll solve(ll * a, ll * b, int n, int m, ll v) {
	if(!n) return 0;
	int p = n / 2;
	ll * iter = std::upper_bound(b, b + m, v - a[p]);
	int c = iter - b;
	return solve(a, iter, p, m - c, v) + solve(a + p + 1, b, n - p - 1, m, v) + (ll) c * (p + 1);
}
ll count(ll * a, ll * b, int n, int m, ll v) {
	int k = 0;
	for(;a[k] + b[k] <= v;++k) ;
	return k * k + solve(a, b + k, k, m - k, v) + solve(b, a + k, k, n - k, v);
}
ll count(ll v) {
	ll sum = 0;
	for(int i = 1;i <= n;++i) {
		sum += count(b + i, c + i, n - i + 1, n - i + 1, v - a[i]);
		sum += count(a + i + 1, c + i, n - i, n - i + 1, v - b[i]);
		sum += count(a + i + 1, b + i + i, n - i, n - i, v - c[i]);
		if(sum > k) return sum;
	}
	return sum;
}
int main() {
	std::ios::sync_with_stdio(false), cin.tie(0);
	cin >> n >> k;
	init(a);
	init(b);
	init(c);
	ll l = 0, r = 3e9 + 10;
	for(;l + 1 < r;) {
		ll mid = (l + r) >> 1;
		if(count(mid) >= k) {
			r = mid;
		} else {
			l = mid;
		}
	}
	cout << r << '\n';
}