1 #include<iostream>
 2 #include<cstdio>
 3 #include<algorithm>
 4 #include<queue>
 5 #include<stack>
 6 #include<iostream>
 7 #include<cstring>
 8 using namespace std;
 9 const int maxn=100005;
10 template<class T>
11 void clear(T &x)
12 {
13     T tmp;swap(x,tmp);
14 }
15 struct node
16 {
17     int from,to,next;
18 }edge[maxn];
19 int head[maxn],tot;
20 void addedge(int u,int v)
21 {
22     edge[++tot]=(node){u,v,head[u]};head[u]=tot;
23 }
24 priority_queue<int>q;
25 stack<int>s;
26 int n,m;
27 int entrance_degree[maxn];
28 int haha()
29 {
30     freopen("dishes.in","r",stdin);
31     freopen("dishes.out","w",stdout);
32     int t;scanf("%d",&t);
33     while(t--)
34     {
35         memset(entrance_degree,0,sizeof(entrance_degree));
36         memset(head,0,sizeof(head));clear(s);tot=0;
37         scanf("%d%d",&n,&m);
38         for(int i=1;i<=m;i++)
39         {
40             int x,y;scanf("%d%d",&x,&y);
41             addedge(y,x);entrance_degree[x]++;
42         }
43         int cnt=0;
44         for(int i=1;i<=n;i++)
45             if(!entrance_degree[i])q.push(i);
46         while(!q.empty())
47         {
48             int l=q.top();q.pop();
49             s.push(l);cnt++;
50             for(int i=head[l];i;i=edge[ i].next)
51             {
52                 int v=edge[i].to;
53                 entrance_degree[v]--;
54                 if(!entrance_degree[v])q.push(v);
55             }
56         }
57         if(cnt!=n)puts("Impossible!");
58         else 
59         {
60             while(!s.empty())
61             {
62                 printf("%d ",s.top());
63                 s.pop();
64             }
65             puts("");
66         }
67     }
68 }
69 int sb=haha();
70 int main(){;}