#include <bits/stdc++.h>
 
using namespace std;
 
const int N = 1e5 + 5, M = 2e5 + 5;
 
int n, m, u, v;
 
vector<int> adj[N];
bool vis[N];
 
void DFS(int u) {       // o(n + m)
  vis[u] = true;
  for (int v : adj[u]) {
    if (!vis[v]) {
      cout << v << " "; 
      DFS(v);
    }
  }
}
 
int main() {
  scanf("%d %d", &n, &m);
  for (int i = 0; i < m; i++) {
    scanf("%d %d", &u, &v);
    adj[u].push_back(v);
    //adj[v].push_back(u);
  }
  DFS(0);
  return 0;
}
 
/*
Samples:
7 6
0 1
1 2
2 5
2 3
2 6
3 4
*/

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NiA1CjAgMQowIDIKMyA0CjQgNQo1IDM=

6 5
0 1
0 2
3 4
4 5
5 3