#include <cstdlib>
#include <cstdio>
#include <vector>
using namespace std;

struct V {
  int key;
  bool passou;
  vector<int> next;
  vector<int> prev;
};
vector<V*> end;
vector<int> pil;
int marc;
int last;
void start(int qn){
    for(int i=0; i<qn; i++){
        V *t;
        t = (V*)malloc(sizeof(V));
        t->key=i;
        t->passou=0;
        end.push_back(& *t);
    }
}

void simular(int qV){
    bool ligC[qV][qV];
    bool hist[qV][qV];
    bool noCactus=0;
    marc = -1;
    last=-1;
    for(int i=0; i<end.size(); i++){
        V *t = end[i];
        if(!(t->passou)){
            last = t->key;
            for(int j=0; j<(t->next).size();j++,marc++){
                V *tAux = end[t->next[j]];
                pil.push_back(tAux->key);
                hist[j][last]=1;
            }
            t->passou=1;

        }
        while(pil[0]!=NULL||noCactus){ // pode acontecer algo no NULL
            V *t1 = end[pil[marc]];

            if(!(t1->passou)){
                last = t1->key;
                pil[marc] = NULL;
                marc--;
                for(int j=0; j<(t1->next).size();j++,marc++){
                        V *tAux = end[t1->next[j]];
                        pil.push_back(tAux->key);
                        hist[j][last]=1;
                        for(int l=0;l<qV;l++,hist[j][l]=1);
                    }
                    t->passou=1;
            }else{
                V *t2 = end[last];
                int fbKey;
                int fb;
                V* t2Aux; // não sei pra que.
                while(pil[0]!=NULL||noCactus||fb==0){
                    t2Aux = t2;
                    fb=0;
                    for(int j=0; j<t2->prev.size() ;j++){
                        V *tAux = end[t2->prev[j]];
                        if(hist[tAux->key][t1->key]&&!(hist[tAux->key][t2->key])) fb++, fbKey=tAux->key;
                    }
                    if(fb>1) noCactus=1;
                }
            }
        }
    }
    noCactus? printf("NO"):printf("YES");
}


int main(){
    int q;
    scanf("%d", &q);
    for(int i=0; i<q; i++){
        int qV, qE;
        scanf("%d %d",&qV, &qE);
        start(qV);

        for(int i=0; i<qE;i++){
            int v1,v2;
            scanf("%d %d",&v1,&v2);

            V *t1 = end[v1];
            V *t2 = end[v2];
            printf("%d\n%d",t1->key,t2->key);
            t1->next.push_back(v2);printf("foi");
            t2->prev.push_back(v1);
        }
    }

}