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# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

// using System.Numerics;

using System.Runtime.CompilerServices;
using System.Diagnostics;
using ll=System.Int64;
using static MyIO;

public class Contest
{
	static void swap1<T>(ref T a,ref T b) { T t = a; a = b; b = t; }
	static void swap2<T>(ref T a,ref T b) where T : IComparable { if (a.CompareTo(b)==1) swap1(ref a,ref b); }  // b の方が小さければ交換
	static bool chmin<T>(ref T a,T b) where T : IComparable { if (a.CompareTo(b)== 1) { a = b; return true; } return false; }  // b の方が小さければ a を更新
	static bool chmax<T>(ref T a,T b) where T : IComparable { if (a.CompareTo(b)==-1) { a = b; return true; } return false; }  // b の方が大きければ a を更新
	static bool inside(long i,long n) => (0<=i&&i<n);
	static bool inside(long x,long y,long w,long h) => (inside(x,w)&&inside(y,h));
	static T min<T>(params T[] a) where T : IComparable => a.Min();
	static T max<T>(params T[] a) where T : IComparable => a.Max();
	static long mod(long a,long m) { var v = a%m; return (v<0?v+m:v); }
	static T[][] init<T>(long len1,long len2,T val) where T : struct { T[][] m = new T[len1][]; for (int i=0;i<m.Length;i++) m[i] = Enumerable.Repeat(val,(int)len2).ToArray(); return m; }
	static T[][][] init<T>(long len1,long len2,long len3,T val) where T : struct { T[][][] m = new T[len1][][]; for (int i=0;i<m.Length;i++) m[i] = init(len2,len3,val); return m; }
	public const long MOD1 = 1000000007; // 10^9+7
	public const double EPS1 = 1e-8;
	public const long INF1 = 1000000000000000;  // 10^15

	public static void Main() => Solve_D();

	public static void Solve_A() {
		long  n, m;
		MyIO.RM(out n, out m);



		var ans = m<=500*n?"Yes":"No";


		MyIO.WM(ans);
	}
	public static void Solve_B() {
		long  n;
		string s;
		MyIO.RM(out n);
		MyIO.RM(out s);



		long ans = 0;
		for (int i = 0; i < n-2; i++)
		{
			if(s[i]=='A'&&s[i+1]=='B'&&s[i+2]=='C') ans++;
		}


		MyIO.WM(ans);
	}
	public static void Solve_C() {
		long  n;
		MyIO.RM(out n);
		ll[] p,q;
		RA(out p);
		RA(out q);

		ll a=0;
		ll b=0;
		var pp = Permutation<ll>.All(1,n);
		int c=0;
		foreach (var e in pp)
		{
			c++;
			bool ba = true;
			bool bb = true;
			for (int j = 0; j < n; j++)
			{
				if(e[j]!=p[j]){
					ba = false;
				}
				if(e[j]!=q[j]){
					bb = false;
				}
			}
			if(ba) a=c; 
			if(bb) b=c; 
		}


		long ans = Math.Abs(a-b);


		MyIO.WM(ans);
	}
	public static void Solve_D() {
		long  n, m;
		MyIO.RM(out n, out m);
		ll[] a;
		RA(out a);

		for (int i = 0; i < n; i++)
		{
			a[i] /=2;
		}

		ll l = LCM(a);

		long ans = m/l;
		ans = (ans+1)/2;




		MyIO.WM(ans);

	}
	public static void Solve_E() {
		long  n;
		MyIO.RM(out n);
		ll[] c;
		RA(out c);




		long ans = 0;


		MyIO.WM(ans);
	}
	public static void Solve_F() {
		long  n, m;
		MyIO.RM(out n, out m);



		long ans = 0;


		MyIO.WM(ans);
	}




public static class Permutation<T>
{
    private static void Search(List<T[]> perms, Stack<T> stack, T[] a)
    {
        int N = a.Length;
        if (N == 0)
        {
            perms.Add(stack.Reverse().ToArray());
        }
        else
        {
            var b = new T[N - 1];
            Array.Copy(a, 1, b, 0, N - 1);
            for (int i = 0; i < a.Length; ++i)
            {
                stack.Push(a[i]);
                Search(perms, stack, b);
                if (i < b.Length) { b[i] = a[i]; }
                stack.Pop();
            }
        }
    }
    public static IEnumerable<T[]> All(IEnumerable<T> src)
    {
        var perms = new List<T[]>();
        Search(perms, new Stack<T>(), src.ToArray());
        return perms;
    }
    public static IEnumerable<int[]> All(long start, long count) => Permutation<int>.All(Enumerable.Range((int)start, (int)count));
}

	public static long GCD(long a, long b) {
	    var v = new[] { a, b };
	    while (v[1] != 0) v = new[] { v[1], v[0] % v[1] };
	    return v[0];
	}
	public static long GCD(params long[] z) { long v = z[0]; for(int i=1;i<z.Length;i++) v = GCD(v, z[i]); return v; }

	public static long LCM(long a, long b) {
		long v = a / GCD(a, b) * b;
		return v<int.MaxValue?v:int.MaxValue;
	}
	public static long LCM(params long[] z) { long v = z[0]; for(int i=1;i<z.Length;i++) v = LCM(v, z[i]); return v; }















}


















#region MyIO

public struct VT<T,U>
{
	public T Item1; public U Item2;
    public VT(T a,U b) { Item1 = a; Item2 = b; }
}
public struct VT<T,U,V>
{
	public T Item1; public U Item2; public V Item3;
    public VT(T a,U b,V c) { Item1 = a; Item2 = b; Item3 = c; }
}
public struct VT<T,U,V,W>
{
	public T Item1; public U Item2; public V Item3; public W Item4;
    public VT(T a,U b,V c,W d) { Item1 = a; Item2 = b; Item3 = c; Item4 = d; }
}

public static class MyIO
{
	class Prt : System.IO.StreamWriter
	{
		public override IFormatProvider FormatProvider { get { return System.Globalization.CultureInfo.InvariantCulture; } }
		public Prt(System.IO.Stream s) : base(s,new UTF8Encoding(false,true)) {}
		public Prt(System.IO.Stream s,Encoding e) : base(s,e) {}
	}
	
	static char[] sp = new char[] {' '};
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	static bool eq<T,U>() => typeof(T).Equals(typeof(U));
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	static T ct<T,U>(U a) => (T)Convert.ChangeType(a,typeof(T));
	static T cv<T>(string s) =>
		eq<T,int>()    ? ct<T,int>(int.Parse(s))
	  : eq<T,long>()   ? ct<T,long>(long.Parse(s))
	  : eq<T,double>() ? ct<T,double>(double.Parse(s,System.Globalization.CultureInfo.InvariantCulture))
	  : eq<T,char>()   ? ct<T,char>(s[0])
					   : ct<T,string>(s);
	public static string[] RM<T>(out T a) {
		var z = Console.ReadLine().Split(sp,StringSplitOptions.RemoveEmptyEntries); 
		a = cv<T>(z[0]);
		return z;
	}
	public static string[] RM<T,U>(out T a,out U b) {
		var z = RM<T>(out a); 
        b = cv<U>(z[1]);
		return z;
	}
	public static string[] RM<T,U,V>(out T a,out U b,out V c) {
		var z = RM<T,U>(out a,out b); 
        c = cv<V>(z[2]);
		return z;
	}
	public static string[] RM<T,U,V,W>(out T a,out U b,out V c,out W d) {
		var z = RM<T,U,V>(out a,out b,out c); 
        d = cv<W>(z[3]);
		return z;
	}
	public static string[] RM<T,U,V,W,X>(out T a,out U b,out V c,out W d,out X e) {
		var z = RM<T,U,V,W>(out a,out b,out c,out d); 
        e = cv<X>(z[4]);
		return z;
	}
	public static string[] RM<T,U,V,W,X,Y>(out T a,out U b,out V c,out W d,out X e,out Y f) {
		var z = RM<T,U,V,W,X>(out a,out b,out c,out d,out e); 
        f = cv<Y>(z[5]);
		return z;
	}
	public static string[] RA<T>(out T[] a) {		
		var z = Console.ReadLine().Split(sp,StringSplitOptions.RemoveEmptyEntries);
		a = z.Select(cv<T>).ToArray();
		return z;
	}
	public static string[][] RL<T>(long n,out T[] a) {
		a = new T[n];
		var y = new string[n][];
		for(int i=0;i<n;i++) y[i] = RM(out a[i]);
		return y;
	}
	public static string[][] RL<T,U>(long n,out VT<T,U>[] a) {
		a = new VT<T,U>[n];
		var y = new string[n][];
		for(int i=0;i<n;i++) {
			T o; U p;
			y[i] = RM(out o,out p);
			a[i] = new VT<T,U>(o,p);
		}
		return y;
	}
	public static string[][] RL<T,U,V>(long n,out VT<T,U,V>[] a) {
		a = new VT<T,U,V>[n];
		var y = new string[n][];
		for(int i=0;i<n;i++) {
			T o; U p; V q;
			y[i] = RM(out o,out p,out q);
			a[i] = new VT<T,U,V>(o,p,q);
		}
		return y;
	}
	public static string[][] RL<T,U,V,W>(long n,out VT<T,U,V,W>[] a) {
		a = new VT<T,U,V,W>[n];
		var y = new string[n][];
		for(int i=0;i<n;i++) {
			T o; U p; V q; W r;
			y[i] = RM(out o,out p,out q,out r);
			a[i] = new VT<T,U,V,W>(o,p,q,r);
		}
		return y;
	}
	public static string[][] RX<T>(long n,out T[][] a) {
		a = new T[n][];
		var y = new string[n][];
		for(int i=0;i<n;i++) y[i] = RA(out a[i]);
		return y;
	}

	static void wwp(Action act){
		var s = new Prt(Console.OpenStandardOutput()){AutoFlush = false};
		Console.SetOut(s);
		act();
		Console.Out.Flush();
		s.AutoFlush = true;
		Console.SetOut(s);
	}
	[MethodImpl(MethodImplOptions.AggressiveInlining)]
	static string wfm(Type t) =>t.Equals(typeof(double)) ? "{0:F10}" : "{0}";
	public static void WM(params object[] a) {
		wwp(()=>{
			for(int i=0;i<a.Length;i++) {
				var f = wfm(a[i].GetType()) + ((i<a.Length-1) ? " " : Environment.NewLine);
				Console.Write(f,a[i]);
			}
		});
	}
	public static void WA<T>(IList<T> a) {
		wwp(()=>{
			var f = wfm(typeof(T));
			var g = f + " ";
			var h = f + Environment.NewLine;
			for(int i=0;i<a.Count;i++) Console.Write(((i<a.Count-1) ? g : h),a[i]);
		});
	}
	public static void WL<T>(IList<T> a) {
		wwp(()=>{
			var f = wfm(typeof(T)) + Environment.NewLine;
			foreach(T x in a) Console.Write(f,x);
		});
	}


}

#endregion