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#include <iostream>
#include<vector>
using namespace std;

long long k;
long long n;


long long findL(vector<int>& ps) {
  for(long long i = n; i > 0; i--) {
    long long l = i;
    for(long long j = k-1; j >= 0; j--) {
      int d = ps[j];
      while(l % d == 0) {
        l = l / d;
      }
      if (l == 1) {
        return i;
      }
    }
  }
  return -1;
}

int main(int argc, const char* argv[]) {
  cin >> k;
  cin >> n;

  vector<int> ps (k);

  for(int i = 0; i < k; i++) {
    cin >> ps[i];
  }

  cout << findL(ps);

  return 0;
}