//看看会不会爆int!数组会不会少了一维！
//取物问题一定要小心先手胜利的条件
#include <bits/stdc++.h>
using namespace std;
#pragma comment(linker,"/STACK:102400000,102400000")
#define LL long long
#define ALL(a) a.begin(), a.end()
#define pb push_back
#define mk make_pair
#define fi first
#define se second
#define haha printf("haha\n")
const int maxn = 100000 + 5;
int n, m;
vector<int> G[maxn];
int in[maxn];
vector<int> ans;

bool solve(){
    priority_queue<int> que;
    ans.clear();
    for (int i = 1; i <= n; i++){
        if (in[i] == 0) que.push(i);
    }
    while (!que.empty()){
        int u = que.top(); que.pop();
        ans.push_back(u);
        for (int i = 0; i < G[u].size(); i++){
            int v = G[u][i]; in[v]--;
            if (in[v] == 0) que.push(v);
        }
    }
    //printf("size = %d\n", ans.size());
    return ans.size() == n;
}

int main(){
    int t; cin >> t;
    while (t--){
        scanf("%d%d", &n, &m);
        for (int i = 1; i <= n; i++) G[i].clear(), in[i] = 0;
        for (int i = 1; i <= m; i++){
            int u, v; scanf("%d%d", &u, &v);
            G[v].pb(u); in[u]++;
        }
        if (!solve()) puts("Impossible!");
        else {
            reverse(ALL(ans));
            for (int i = 0; i < ans.size(); i++){
                printf("%d ", ans[i]);
            }
            cout << endl;
        }
    }
    return 0;
}