#include <bits/stdc++.h>
using std::cin;
using std::cout;
using std::endl;
using ll = long long;
std::mt19937 rnd(std::chrono::steady_clock::now().time_since_epoch().count());

template <class T>
inline bool chmax(T &a, T b) {
  if (a < b) {
    a = b;
    return 1;
  }
  return 0;
}

template <class T>
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() {
  int n, K;
  cin >> n >> K;
  std::vector<int> a(n);
  for (int i = 0; i < n; ++i) {
    cin >> a[i];
  }
  std::sort(a.rbegin(), a.rend());
  a.erase(std::unique(a.begin(), a.end()), a.end());
  n = (int)a.size();
  ll res = 0;
  auto dfs = [&](auto &&self, int cur, ll val) -> void {
    if (cur == n - 1) {
      chmax(res, val % a[cur]);
      return;
    }
    self(self, cur + 1, val);
    self(self, cur + 1, val % a[cur]);
  };
  dfs(dfs, 0, K);
  cout << res << "\n";
}

int main() {
  std::cin.tie(nullptr);
  std::ios::sync_with_stdio(false);

  int I_love_KKT89 = 1;
  // cin >> I_love_KKT89;
  for (int Case = 1; Case <= I_love_KKT89; ++Case) {
    // cout << "Case #" << Case << ": ";
    solve();
  }
  return 0;
}