#include <iostream>
#include <string>
#include <vector>
#include <functional>
#include <algorithm>
#include <numeric>
#include <map>
using namespace std;
#define FOR(i,n) for (int i=0;i<(int)n;i++)
#define FORN(i,a,b) for (int i=a;i<=(int)b;i++)

bool f(vector<int> &v, int casenum)
{
	vector<int> res(v.size()+1);

	int max=0;
	int recordA=0;
	bool globalFound=false;
	FORN(a,1,v[0])
	{
		bool found=true;
		res[0]=a;
		FORN(i,1,res.size()-1)
		{
			res[i]=v[i-1]-res[i-1];
			if (res[i]<1) found=false;
		}
		if (found)	//now find max product
		{
			int tmax=(int)accumulate (res.begin(), res.end(), 1, multiplies<int>());
			if (tmax>max)
			{
				max=tmax;
				recordA=a;
				globalFound=true;
			}
		}
	}

	if (!globalFound)
	{
		cout<<"Case "<<casenum<<": Impossible Sums!\n";
		return false;
	}


	//get the winning sequencez
	res[0]=recordA;
	FORN(i,1,res.size()-1) res[i]=v[i-1]-res[i-1];
	cout<<"Case "<<casenum<<": ";
	cout<<res[0];
	FORN(i,1,res.size()-1) cout<<" "<<res[i];cout<<endl;

	return true;
}


int main()
{
	int n;
	int casenum=1;
	while(cin>>n && n!=0)
	{
		vector<int> v(n);
		FOR(i,n) cin>>v[i];
		f(v,casenum++);
	}

	return 0;
}