#include <iostream>

#include <cstdio>

#include <cstring>

#include <queue>

using namespace std;

#define N 100005

int n, m, tp, Q[N], in[N];

int cnt,hd[N],nxt[N<<],ed[N],poi[N<<];

inline void add(int x,int y){

    nxt[ed[x]]=++cnt, hd[x]=hd[x]?hd[x]:cnt,

    ed[x]=cnt, poi[cnt]=y, ++in[y];

}

void bfs() {

    priority_queue<int> h;

    for (int i = ; i <= n; ++i)

        if (!in[i]) h.push(i);

    while (!h.empty()) {

        int x = h.top(); h.pop();

        Q[++tp] = x;

        for(int i=hd[x];i;i=nxt[i]){

            --in[poi[i]];

            if(in[poi[i]]==) h.push(poi[i]);

        }

    }

}

int main() {

    int T; scanf("%d",&T);

    while(T--){

        memset(in,,sizeof(in));

        memset(hd,,sizeof(hd));

        memset(ed,,sizeof(ed));

        memset(nxt,,sizeof(nxt)); tp=cnt=;

        scanf("%d%d", &n, &m);

        for (int i = , f, t; i <= m; ++i)

            scanf("%d%d", &f, &t),add(t,f);

        bfs();

        if (tp < n) {puts("Impossible!");continue;}

        for (int i = n;i; --i) printf("%d ", Q[i]);

        printf("\n");

    }

    return ;

}