Problem:
Score : 400 points

Problem Statement

Given are a sequence A= {a_1,a_2,......a_N} of N positive even numbers, and an integer M.

Let a semi-common multiple of A be a positive integer X that satisfies the following condition for every k (1 \leq k \leq N):

There exists a non-negative integer p such that X= a_k \times (p+0.5).

Find the number of semi-common multiples of A among the integers between 1 and M (inclusive).

Constraints

1 \leq N \leq 10^5

1 \leq M \leq 10^9

2 \leq a_i \leq 10^9

a_i is an even number.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M
a_1 a_2 ... a_N

Output

Print the number of semi-common multiples of A among the integers between 1 and M (inclusive).

Sample Input 1

2 50
6 10

Sample Output 1

2

15 = 6 \times 2.5

15 = 10 \times 1.5

45 = 6 \times 7.5

45 = 10 \times 4.5

Thus, 15 and 45 are semi-common multiples of A. There are no other semi-common multiples of A between 1 and 50, so the answer is 2.

Sample Input 2

3 100
14 22 40

Sample Output 2

0

The answer can be 0.

Sample Input 3

5 1000000000
6 6 2 6 2

Sample Output 3

166666667

Solution in C++14 (GCC 5.4.1) (judge verdict: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

ll gcd(ll a, ll b){return b==0 ? a : gcd(b, a%b);}
ll lcm(ll a, ll b){return a / gcd(a,b) * b;}

vector<ll> divisor(ll n)
{
  vector<ll> res;
  for (int i=1; i*i<=n; i++) {
    if (n%i == 0) {
      res.push_back(i);
      if (i != n/i) res.push_back(n/i);
    }
  }
  sort(res.begin(), res.end());
  return res;
}

int main()
{
  ll N;
  cin >> N;
  ll M;
  cin >> M;
  vector<ll> a(N);
  for (int i=0; i<N; i++){
    cin >> a[i];
    a[i] /= 2;
  }

  ll l = 1;
  for (int i=0; i<N; i++) {
    l = lcm(l, a[i]);
  }
  cout << ((M/l)+1)/2 << endl;

  return 0;
}