#include <bits/stdc++.h> using namespace std; struct iofast_t { iofast_t() { ios::sync_with_stdio(false); cin.tie(nullptr); } } iofast; struct uns_t {} uns; template <typename Element, typename Head, typename ...Args> auto vec(Element init, Head arg, Args ...args) { if constexpr (sizeof...(Args) == 0) return std::vector(arg, init); else return std::vector(arg, vec(init, args...)); } template <typename Element, typename Head, typename ...Args> auto vec(uns_t, Head arg, Args ...args) { return vec(Element(), arg, args...); } template <typename T, typename Compare = less<T>> T &chmin(T &l, T r, Compare &&f = less<T>()) { return l = min(l, r, f); } template <typename T, typename Compare = less<T>> T &chmax(T &l, T r, Compare &&f = less<T>()) { return l = max(l, r, f); } int main() { int64_t n, k, p; cin >> n >> k >> p; auto a = vec<int>(uns, n); auto b = vec<int>(uns, n); for (auto &e : a) cin >> e; for (auto &e : b) cin >> e; sort(begin(a), end(a)); sort(begin(b), end(b)); auto count = [&](int x) { int64_t ans = 0; for (auto v : a) { auto last = lower_bound(begin(b), end(b), p - v); ans += distance(begin(b), upper_bound(begin(b), last, x - v)); ans += distance(last, upper_bound(last, end(b), x - v + p)); } return ans; }; int l = -1, r = p; while (1 < r - l) { int m = l + (r - l) / 2; if (count(m) < k) { l = m; } else { r = m; } } cout << r << endl; }