#include <bits/stdc++.h>
#include <random>

using namespace std;

typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
//#define int ll
//#define int __int128
//#define ll __int128
typedef pair<int, int   > pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vpi;
typedef vector< vi > vvi;
typedef vector< vvi > vvvi;
typedef vector<short> vs;
typedef vector<vs> vvs;
typedef vector<vvs> vvvs;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<vvl> vvvl;
typedef vector<ld> vld;
typedef vector<vld> vvld;
typedef vector<vvld> vvvld;
typedef vector<string> vst;
typedef vector<vst> vvst;
typedef pair<ld, ld> pld;
//typedef complex<double> base;

#define inmin(a, b) a = min(a, (b))
#define inmax(a, b) a = max(a, (b))
#define ALL(a) a.begin(),a.end()
#define RALL(a) a.rbegin(),a.rend()
#define sqr(x) ((x) * (x))
#define fori(i, n) for(int i = 0; i < (int)(n); ++i)
#define SZ(a) ((int)((a).size()))
#define triple(T) tuple<T, T, T>
#define quad(T) tuple<T, T, T, T>
#define watch(x) cerr << (#x) << " = " << (x) << endl;
#define mp(a, b) make_pair(a, b)

#ifdef MAX_HOME
#define cerr cout
#else
#define cerr if (false) cerr
#endif

const double PI = 2 * acos(0.0);
#define rand shittttty_shit
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());

const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";

template <class T0, class T1>
inline ostream & operator << (ostream &out, pair<T0, T1> &a) {
    return out << "{" << a.first << ", " << a.second << "}";
}

template <class T0, class T1, class T2>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << "}";
}

template <class T0, class T1, class T2, class T3>
inline ostream & operator << (ostream &out, tuple<T0, T1, T2, T3> &a) {
    return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a) << ", " <<  get<3>(a) << "}";
}

template<class T>
inline ostream & operator << (ostream &out, vector<T> &a) {
    out << "[";
    fori (i, a.size())
        out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
    return out;
}



void smain();

signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

#ifdef MAX_HOME
    freopen("input.txt", "r", stdin);
    clock_t start = clock();
#endif
    cout << setprecision(12) << fixed;
    smain();
#ifdef MAX_HOME
    cout << "\n\n\n\nTOTAL EXECUTION TIME: " << float( clock () - start ) /  CLOCKS_PER_SEC << endl;
#endif
    return 0;
}



void smain() {
    int sm, n;
    cin >> sm >> n;
    vi a;
    vi odd;
    fori (i, n) {
        int cur;
        cin >> cur;
        if (cur & 1) {
            odd.push_back(cur);
        } else {
            a.push_back(cur);
        }
    }
    if (odd.size() >= 3) {
        cout << "Impossible";
        return;
    }
    vi b;
    if (odd.size()) {
        a.insert(a.begin(), odd[0]);
    }
    if (odd.size() == 2) {
        a.push_back(odd[1]);
    }
    if (a.size() == 1 && (a[0] & 1)) {
        if (a[0] - 1)
            b.push_back(a[0] - 1);
        b.push_back(1);
    } else {
        for (int i = 0; i < (int) a.size(); ++i) {
            if (a[i] & 1) {
                if (i + 1 == n) {
                    b.push_back(2);
                    if (a[i] - 1)
                        b.push_back(a[i] - 1);
                } else {
                    if (a[i] - 1)
                        b.push_back(a[i] - 1);
                }
            } else {
                if (i == 0) {
                    if (a[i] - 2)
                        b.push_back(a[i] - 2);
                    b.push_back(1);
                } else {
                    b.push_back(a[i]);
                }
            }
        }
    }
    if (!(a.back() & 1)) {
        b.push_back(1);
//        watch("kek");
    }
    for (auto x : a) {
        cout << x << ' ';
    }
    cout << '\n';
    cout << b.size() << '\n';
    for (auto x : b) {
        cout << x << ' ';
    }
}


Measured memory_bytes: 256