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Huhu_Miao: 2024-11-20 09:02:44
/**
 *    author:  Huhu_Miao
 *    created: 2024.11.20 09:01:00 (UTC+8)
**/

#include<bits/stdc++.h>

void printVector(const std::vector<int> & vec){
	for(const int & elem : vec){
		std::cout << elem << ' ';
	}
	std::cout << '\n';
}

void solve(){
	int n, m;
	std::cin >> n >> m;
	std::vector<int> inDegree(n+1,0);
	std::vector<std::vector<int>> g(n+1,std::vector<int>(0));
	std::vector<int> ans;
	while(m--){
		int from, to;
		std::cin >> from >> to;
		g[from].push_back(to);
		inDegree[to]++;
	}
	std::queue<int> q;
	for(int i = 1 ; i < n+1 ; i++){
		if(inDegree[i] == 0) q.push(i);
	}
	while(!q.empty()){
		ans.push_back(q.front());
		for(auto elem : g[q.front()]){
			inDegree[elem]--;
			if(inDegree[elem] == 0) q.push(elem);
		}
		q.pop();
	}
	if(ans.size() != n){
		std::cout << 0 << '\n';
	}else{
		printVector(ans);
	}
}

int main(){
	std::ios::sync_with_stdio(false); std::cin.tie(nullptr);
	int T; std::cin>>T;
	while(T--) solve();
	return 0;
}