#include <iostream>
#include <algorithm>
#include <queue>

using namespace std;

const int N = 10010;

struct Node{
    int id;
    Node *next;
    Node(int _id): id(_id), next(NULL){}
}* head[N];
bool read[N];

void add(int x, int y)
{
    auto p = new Node(y);
    p->next = head[x];
    head[x] = p;
}

/*void dfs(int t)
{
    read[t] = true;
    cout << t << " ";
    for(auto p=head[t]; p; p=p->next)
    {
        int o=p->id;
        if(!read[o]) dfs(o);
    }
}
*/

void bfs(){
    queue<int> q;
    q.push(1);
    read[1] = true;

    while(q.size()){
        auto o = q.front();
        q.pop();

        cout << o << " ";
        for(auto p=head[o]; p; p=p->next)
        {
            int j = p->id;
            if(!read[j])
            {
                read[j] = true;
                q.push(j);
            }
        }
    }
}

int main()
{
    int n, m;
    cin >> n >> m;
    while(m--)
    {
        int x, y;
        cin >> x >> y;
        add(x,y);
    }

/*    for(int i=1; i<=n; i++)
    {
        if(!read[i]) dfs(i);
    }
*/
    bfs();
    return 0;
}

```