// bzoj4010#include<algorithm>#include<iostream>#include<cstring>#include<cstdlib>#include<cstdio>#include<cmath>#include<queue>#define MOD 1000000007#define inf 2147483640#define LL long long#define free(a) freopen(a".in","r",stdin);freopen(a".out","w",stdout);using namespace std;const int maxn=100010;struct edge {int to,next;}e[maxn<<1];priority_queue<int> q;int head[maxn],ans[maxn],d[maxn],n,m,top,cnt;void link(int u,int v) {    e[++cnt].to=v;e[cnt].next=head[u];head[u]=cnt;}int main() {    int T;scanf("%d",&T);    while (T--) {        scanf("%d%d",&n,&m);cnt=0;        memset(head,0,sizeof(head));memset(d,0,sizeof(d));        for (int u,v,i=1;i<=m;i++) {            scanf("%d%d",&u,&v);            link(v,u);d[u]++;        }        top=0;        while (q.size()) q.pop();        for (int i=1;i<=n;i++) if (!d[i]) q.push(i);        while (q.size()) {            int x=q.top();q.pop();            ans[++top]=x;            for (int i=head[x];i;i=e[i].next) {                d[e[i].to]--;                if (d[e[i].to]==0)                    q.push(e[i].to);            }        }        if (top!=n) printf("Impossible!\n");        else {            for (int i=n;i>=1;i--) printf("%d ",ans[i]);            printf("\n");        }    }    return 0;}