using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Text;
using System.Globalization;
using System.Diagnostics;



class Myon
{
    public Myon() { }
    public static int Main()
    {
        new Myon().calc();
        return 0;
    }


    Scanner cin;

    void calc()
    {
        cin = new Scanner();
        int N = cin.nextInt();
        int M = cin.nextInt();
        int[] A = cin.ArrayInt(M);

        List<int> even = new List<int>();
        List<int> odd = new List<int>();
        foreach (var item in A)
        {
            if(item % 2 == 0)
            {
                even.Add(item);
            }
            else
            {
                odd.Add(item);
            }
        }

        if(odd.Count >= 3)
        {
            Console.WriteLine("Impossible");
            return;
        }

        List<int> ansA = new List<int>();

        List<int> ansB = new List<int>();
        if (M == 1)
        {
            ansA.Add(A[0]);
            if (A[0] != 1) ansB.Add(A[0] - 1);
            ansB.Add(1);
        }
        else
        {
            if (odd.Count >= 1) ansA.Add(odd[0]);
            foreach (var item in even)
            {
                ansA.Add(item);
            }
            if (odd.Count >= 2) ansA.Add(odd[1]);

            for (int i = 0; i < ansA.Count; i++)
            {
                int num = ansA[i];
                if (i == 0)
                {
                    if (num != 1) ansB.Add(num - 1);
                    ansB.Add(2);
                }
                else if (i == ansA.Count - 1)
                {
                    if (num != 1) ansB.Add(num - 1);
                }
                else
                {
                    ansB.Add(num);
                }
            }
        }
        Console.WriteLine(string.Join(" ", ansA));
        Console.WriteLine(ansB.Count);
        Console.WriteLine(string.Join(" ", ansB));


    }
}



class Scanner
{
    string[] s;
    int i;

    char[] cs = new char[] { ' ' };

    public Scanner()
    {
        s = new string[0];
        i = 0;
    }

    public string next()
    {
        if (i < s.Length) return s[i++];
        string st = Console.ReadLine();
        while (st == "") st = Console.ReadLine();
        s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
        if (s.Length == 0) return next();
        i = 0;
        return s[i++];
    }

    public int nextInt()
    {
        return int.Parse(next());
    }
    public int[] ArrayInt(int N, int add = 0)
    {
        int[] Array = new int[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextInt() + add;
        }
        return Array;
    }

    public long nextLong()
    {
        return long.Parse(next());
    }

    public long[] ArrayLong(int N, long add = 0)
    {
        long[] Array = new long[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextLong() + add;
        }
        return Array;
    }

    public double nextDouble()
    {
        return double.Parse(next());
    }


    public double[] ArrayDouble(int N, double add = 0)
    {
        double[] Array = new double[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextDouble() + add;
        }
        return Array;
    }
}


Measured memory_bytes: 13268