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;
const int MOD = 1e9 + 7;
const int iinf = 1 << 28;
const long long llinf = 1ll << 60;
const double PI = 3.14159265;

ll N, M;
vector<ll> v;

ll gcd(ll a, ll b) {
    if (b == 0)
        return a;
    return gcd(b, a%b);
}


int main() {
    cin >> N >> M;
    for (ll i = 0; i < N; ++i) {
        ll a; cin >> a; v.push_back(a>>1);
    }
    ll lcm = v[0];
    for (int i = 1; i < N; ++i) {
        lcm = (lcm * v[i]) / gcd(lcm, v[i]);
    }

    ll ans = 0;
    for (ll i = lcm; i <= M; i += (lcm<<1)) ++ans;

    cout << ans << endl;

    return 0;
}