#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using ll = long long;
#define int ll
#define rng(i, a, b) for (int i = int(a); i < int(b); i++)
#define rep(i, b) rng(i, 0, b)
#define ALL(a) (a).begin(), (a).end()
template <class t, class u> void chmax(t& a, u b) {
    if (a < b) a = b;
}
template <class t, class u> void chmin(t& a, u b) {
    if (b < a) a = b;
}
template <class t> using vc = vector<t>;
template <class t> using vvc = vc<vc<t>>;
using pi = pair<int, int>;
using vi = vc<int>;
using uint = unsigned;
using ull = unsigned long long;
int popcount(signed t) { return __builtin_popcount(t); }
int popcount(ll t) { return __builtin_popcountll(t); }
bool ispow2(int i) { return i && (i & -i) == i; }
ll mask(int i) { return (ll(1) << i) - 1; }
int lcm(int a, int b) { return a / __gcd(a, b) * b; }
signed main() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    cout << fixed << setprecision(20);
    int n, k, p;
    cin >> n >> k >> p;
    vi a(n), b(n);
    rep(i, n) cin >> a[i];
    rep(i, n) cin >> b[i];
    sort(ALL(a));
    sort(ALL(b));
    //[0,P-1]で並ぶ．二分探索で探っていく
    // (Ai+Bj)%p<midとなる組はk個未満か？
    // watch:https://yukicoder.me/submissions/676067
    int l = -1, r = p;
    // while (r - l > 1) {
    //     int mid = (l + r) / 2;
    //     int cnt = 0;
    //     //mid以下の要素を数える
    //     rep(i, n) {

    //     }
    //     if (cnt > k) {
    //         r = mid;
    //     } else {
    //         l = mid;
    //     }
    // }
    cout << l << endl;
}