#include <memory.h>
#include <iostream>
#include <queue>
#include <cassert>

using namespace std;

class E
{
public:
    int to, val;
    E(int a, int b)
    {
        to = a; val = b;
    }
    /*
    bool friend operator < (const E &A, const E &B)
    {
        return A.val > B.val;
    }
     */
};

bool operator > (const E &A, const E &B)
{
    return A.val > B.val;
}

void solve();
vector <int> dijkstra(vector <vector <E> > A, int head, int target);
int N, M;

int main()
{
    int T;
    cin >> T;
    while(T--)
        solve();
}

void solve()
{
    vector <vector <E> > A;
    vector <vector <E> > B;
    cin >> N >> M;
    A.resize(N);
    B.resize(N);
    for(int i=0; i<M; i++)
    {
        int temp[2];
        cin >> temp[0] >> temp[1];
        A[temp[0]-1].push_back(E(temp[1]-1,1));
        B[temp[1]-1].push_back(E(temp[0]-1,1));
    }
    vector <int> AA = dijkstra(A,0,N-1);
    vector <int> BB = dijkstra(B,N-1,0);
    assert(AA[N-1] == BB[0]);
    for(int i=0; i<N; i++)
        if(AA[i] + BB[i] == AA[N-1])
            cout << i+1 << " ";
    cout << endl;
}

vector <int> dijkstra(vector <vector <E> >A, int head, int target)
{
    vector <int> result;
    result.resize(N);
    for(int i=0; i<N; i++)
        result[i] = -1;
    priority_queue<E, deque<E>, greater<deque<E>::value_type> > C;
    int count = 0;
    result[head] = 0;
    while(count++ < N-1)
    {
        for(int i=0; i<A[head].size(); i++)
            C.push(E(A[head][i].to, 1 +result[head]));
        while(result[C.top().to] != -1)
        {
            C.pop();
            assert(!C.empty()); //here
        }
        head = C.top().to;
        result[head] = C.top().val;
        C.pop();
    }
    return result;
}