#include<bits/stdc++.h>
int n,m,a[101],c[101],b[201],e,sum,now;
int main()
{
	scanf("%d%d",&n,&m);
	if(m==1)
	{
		printf("%d\n",n);
		if(n==1)puts("1"),puts("1");
		else puts("2"),printf("%d %d\n",n-1,1);
		return 0;
	}
	for(int i=1;i<=m;++i)
		scanf("%d",&a[i]),sum+=a[i],now+=a[i]/2;
	now+=sum/2;
	if(now<sum-1)puts("Impossible");
	else 
	{
		for(int i=1;i<=m;++i)
			if(a[i]&1)
			{
				if(c[1])c[m]=a[i];
				else c[1]=a[i];	
				a[i]=0;
			}
		for(int i=1,j=c[1]?1:0;i<=m;++i)
			if(a[i])
				c[++j]=a[i];
		for(int i=1;i<=m;++i)
			b[i]=c[i];
		++b[1];
		e=m;
		--b[m];
		if(c[m]==1)--e;
		for(int i=1;i<=m;++i)
			printf("%d ",c[i]);
		puts("");
		printf("%d\n",e);
		for(int i=1;i<=e;++i)
			printf("%d ",b[i]);
		puts("");
	}
}
#include <bits/stdc++.h>
using namespace std;


#define li          long long int
#define rep(i,to)   for(li i=0;i<((li)(to));i++)
#define repp(i,start,to)    for(li i=(li)(start);i<((li)(to));i++)
#define pb          push_back
#define sz(v)       ((li)(v).size())
#define bgn(v)      ((v).begin())
#define eend(v)     ((v).end())
#define allof(v)    (v).begin(), (v).end()
#define dodp(v,n)       memset(v,(li)n,sizeof(v))
#define bit(n)      (1ll<<(li)(n))
#define mp(a,b)     make_pair(a,b)
#define rin rep(i,n)
#define EPS 1e-12
#define ETOL 1e-8
#define MOD 1000000007
typedef pair<li, li> PI;

#define INF bit(60)

#define DBGP 1


#define idp if(DBGP)
#define F first
#define S second
#define p2(a,b)     idp cout<<a<<"\t"<<b<<endl
#define p3(a,b,c)       idp cout<<a<<"\t"<<b<<"\t"<<c<<endl
#define p4(a,b,c,d)     idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<endl
#define p5(a,b,c,d,e)       idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<endl
#define p6(a,b,c,d,e,f)     idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<endl
#define p7(a,b,c,d,e,f,g)       idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<endl
#define p8(a,b,c,d,e,f,g,h)     idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<"\t"<<h<<endl
#define p9(a,b,c,d,e,f,g,h,i)       idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<"\t"<<h<<"\t"<<i<<endl
#define p10(a,b,c,d,e,f,g,h,i,j)        idp cout<<a<<"\t"<<b<<"\t"<<c<<"\t"<<d<<"\t"<<e<<"\t"<<f<<"\t"<<g<<"\t"<<h<<"\t"<<i<<"\t"<<j<<endl
#define foreach(it,v)   for(__typeof((v).begin()) it=(v).begin(); it!=(v).end(); ++it)
#define p2p(x)      idp p2((x).F, (x).S)
#define dump(x,n)   idp{rep(i,n){cout<<x[i]<<" ";}puts("");}
#define dump2(x,n)  idp{rep(i,n){cout<<"["<<x[i].F<<" , "<<x[i].S<<"] ";}puts("");}
#define dumpi(x)    idp{foreach(it, x){cout<<(*it)<<" ";}puts("");}
#define dumpi2(x)   idp{foreach(it, x){cout<<"["<<(it)->F<<" , "<<(it)->S<<"] ";}puts("");}

#define read2d(a,w,h)   rep(i,h)rep(j,w)cin>>a[i][j]
#define dump2d(a,w,h)   rep(i,h){rep(j,w)cout<<a[i][j]<<" ";puts("");}

typedef pair<li, li> PI;

li n, m;
li a[111];

int main() {
    cin >> n >> m;
    li odd_cnt = 0;
    rep(i, m) {
        cin >> a[i];
        if (a[i] % 2 > 0) {
            odd_cnt++;
        }
    }

    if (odd_cnt > 2) {
        puts("Impossible");
        return 0;
    }

    vector<li> res;
    rep(i, m) {
        if (a[i] % 2 > 0 && i != 0) {
            swap(a[0], a[i]);
            break;
        }
    }
    rep(i, m - 1) {
        if (a[i] % 2 > 0 && i != 0) {
            swap(a[i], a[m - 1]);
            break;
        }
    }
    rep(i, m) {
        cout << a[i] << " ";
    } cout << endl;

    if (m == 1) {
        if (a[0] == 1) {
            cout << 1 << endl;
            cout << 1 << endl;
        } else {
            cout << 2 << endl;
            cout << a[0] - 1 << " " << 1 << endl;
        }
        return 0;
    }

    if (a[0] > 1)res.pb(a[0] - 1);
    res.pb(2);
    rep(i, m - 2) {
        res.pb(a[i + 1]);
    }
    if (a[m - 1] > 1)res.pb(a[m - 1] - 1);

    cout << sz(res) << endl;
    rep(i, sz(res))cout << res[i] << " ";
    cout << endl;


    return 0;
}