#include <bits/stdc++.h>
using namespace std;

ifstream fin("ciclueuler.in");
ofstream fout("ciclueuler.out");

const int MAX_SIZE = 100000;

vector<int> graph[MAX_SIZE + 1];
vector<int> answer;

void deleteEdge(int node1, int node2) {
    for (vector<int>::iterator it = graph[node1].begin(); it < graph[node1].end(); ++it) {
        if (*it == node2) {
            graph[node1].erase(it);
            return;
        }
    }
}

void euler(int currentNode) {
    while (graph[currentNode].empty() == 0) {
        int nextNode = *graph[currentNode].begin();
        deleteEdge(currentNode, nextNode);
        deleteEdge(nextNode, currentNode);
        euler(nextNode);
    }
    answer.push_back(currentNode);
}

int main() {
    int noNodes, noEdges;
    fin >> noNodes >> noEdges;
    for (int i = 1; i <= noEdges; ++i) {
        int startNode, endNode;
        fin >> startNode >> endNode;
        graph[startNode].push_back(endNode);
        graph[endNode].push_back(startNode);
    }
    euler(1);
    for (int i = 0; i < answer.size(); ++i) {
        fout << answer[i] << ' ';
    }
    return 0;
}