#include <bits/stdc++.h>
using namespace std;
int main(){
  random_device rnd;
  mt19937 mt(rnd());
  int N, K;
  cin >> N >> K;
  vector<int> A(N);
  for (int i = 0; i < N; i++){
    cin >> A[i];
  }
  int ans = 0;
  for (int i = 0; i < 10000; i++){
    vector<int> B = A;
    shuffle(B.begin(), B.end(), mt);
    int X = K;
    for (int j = 0; j < N; j++){
      X %= B[j];
    }
    ans = max(ans, X);
  }
  cout << ans << endl;
}