#include<bits/stdc++.h>
using namespace std;
const int N=1e5+10;
vector<int>G[N];deque<int>ans;int v[N],rd[N],cd[N],cnt;set<int>s;
void solve()
{
	memset(G,0,sizeof(G));ans.clear();memset(v,0,sizeof(v)),memset(rd,0,sizeof(rd)),cnt=0,s.clear();
	int n,m;cin>>n>>m;
	for(int i=1;i<=m;i++)
	{
		int x,y;cin>>x>>y;
		G[y].push_back(x);
		rd[x]++;
	}
	priority_queue<int>q;
	for(int i=1;i<=n;i++)if(rd[i]==0)q.push(i);
	while(!q.empty())
	{
		int x=q.top();q.pop();v[x]=1;ans.push_front(x);
		for(int y:G[x])
		{
			rd[y]--;
			if(rd[y]==0)q.push(y);
		}
	}
	if(ans.size()!=n)
	{
		cout<<"Impossible!\n";
		return;
	}
	for(int y:ans)cout<<y<<" ";cout<<'\n';
}
int main()
{
	ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	int t;cin>>t;
	while(t--)solve();
	return 0;
}