#include <iostream>
using namespace std;

int main()
{
	int t;
	cin>>t;
	while(t--)
	{
		int k;
		cin>>k;
		char f[k+1];
		cin>>f;
		long long n;
		cin>>n;
		bool o[k];
		long long bign=0;
		for(int i=0;i<k;i++)
		{
			if(f[i]=='p')
			{
				bign+=(long long)(1<<(k-i-1));
				o[i]=true;
			}else
			        o[i]=false;
		}
		if(bign<n)
		{
			cout<<"Impossible";
			goto ending;
		}
		bign=bign-n;
		for(int i=0;i<k;i++)
		{
			if((long long)(bign&(long long)(1<<(k-i-1)))!=0)
				o[i]=!o[i];
			cout<<o[i];
		}
		ending:
                        cout<<endl;
		
	}
	return 0;
}