#include using ll = long long; using std::cin; using std::cout; using std::endl; std::mt19937 rnd(std::chrono::steady_clock::now().time_since_epoch().count()); template inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; } const int inf = (int)1e9 + 7; const long long INF = 1LL << 60; void solve() { ll n, K, P; cin >> n >> K >> P; std::vector a(n), b(n); for (int i = 0; i < n; ++i) { cin >> a[i]; } for (int i = 0; i < n; ++i) { cin >> b[i]; } std::sort(a.begin(), a.end()); std::sort(b.begin(), b.end()); ll lf = -1; ll rg = P - 1; while(rg - lf > 1) { ll mid = (lf + rg) >> 1; ll cnt = 0; for (int i = 0; i < n; ++i) { if(a[i] < mid) { ll r = mid - a[i]; cnt += std::upper_bound(b.begin(), b.end(), r) - b.begin(); } { ll r = P - a[i]; cnt += std::upper_bound(b.begin(), b.end(), r + mid) - std::lower_bound(b.begin(), b.end(), r); } } if(cnt < K) { lf = mid; } else { rg = mid; } } cout << rg << "\n"; } int main() { std::cin.tie(nullptr); std::ios::sync_with_stdio(false); int kkt = 1; // cin >> kkt; while(kkt--) solve(); return 0; }