> #include<iostream>
> #include<algorithm>
> 
> using namespace std;
> 
> #define N 30
> 
> int b[N];
> int a[N][N];
> 
> int n;
> 
> int count()
> {
> 	int t=0;
> 	for (int i=1;i<=n-1;i++)
> 	{
> 		int row=i;
> 		for (int k=i+1;k<=n;k++)
> 			if (a[i][i]<a[k][i])
> 				row=k;
> 		if (row!=i)
> 		{
> 			for (int k=i;k<=n;k++)
> 				swap(a[i][k],a[row][k]);
> 			swap(b[i],b[row]);
> 		}
> 
> 		if (a[i][i]==0) continue;
> 		t=i;
> 
> 		for (int k=i+1;k<=n;k++)
> 		{
> 			if (a[k][i]!=0)
> 			{
> 				for (int j=i;j<=n;j++)
> 					a[k][j]^=a[i][j];
> 				b[k]^=b[i];
> 			}
> 		}
> 	}
> 
> 	if (t==n-1)
> 		if (a[n][n]==1)
> 			t++;
> 
> 	for (int k=t+1;k<=n;k++)
> 		if (b[k]!=0) return 0;
> 	
> 	return (1<<(n-t));
> }
> 
> 
> int main()
> {
> 	int k;
> 	cin>>k;
> 	while (k--)
> 	{
> 		memset(a,0,sizeof(a));
> 		cin>>n;
> 		for (int i=1;i<=n;i++)
> 			cin>>b[i];
> 		for (int i=1;i<=n;i++)
> 		{
> 			int end;
> 			cin>>end;
> 			b[i]^=end;
> 
> 			a[i][i]=1;
> 		}
> 		int start,end;
> 		while ((cin>>start>>end)&&(start||end))
> 			a[end][start]=1;
> 
> 		int t=count();
> 		if (t==0)
> 			cout<<"Oh,it's impossible~!!"<<endl;
> 		else
> 			cout<<t<<endl;
> 	}
> 	return 0;
> }