#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define vt vector
#define all(x) begin(x), end(x)
#define allr(x) rbegin(x), rend(x)
#define ub upper_bound
#define lb lower_bound
#define db double
#define ld long db
#define ll long long
#define ull unsigned long long
#define vi vt<int>
#define vvi vt<vi>
#define vvvi vt<vvi>
#define pii pair<int, int>
#define vpii vt<pii>
#define vvpii vt<vpii>
#define vll vt<ll>
#define vvll vt<vll>
#define pll pair<ll, ll>
#define vpll vt<pll>
#define vvpll vt<vpll>
#define ar(x) array<int, x>
#define var(x) vt<ar(x)>
#define vvar(x) vt<var(x)>
#define al(x) array<ll, x>
#define vall(x) vt<al(x)>
#define vvall(x) vt<vall(x)>
#define vs vt<string>
#define pb push_back
#define ff first
#define ss second
#define rsz resize
#define sum(x) (ll)accumulate(all(x), 0LL)
#define srt(x) sort(all(x))
#define srtR(x) sort(allr(x))
#define srtU(x) sort(all(x)), (x).erase(unique(all(x)), (x).end())
#define rev(x) reverse(all(x))
#define MAX(a) *max_element(all(a))
#define MIN(a) *min_element(all(a))
#define SORTED(x) is_sorted(all(x))
#define ROTATE(a, p) rotate(begin(a), begin(a) + p, end(a))
#define i128 __int128
#define IOS ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#if defined(LOCAL) && __has_include("debug.h")
#include "debug.h"
#else
#define debug(...)
#define startClock
#define endClock
inline void printMemoryUsage() {}
#endif
template<class T> using max_heap = priority_queue<T>; template<class T> using min_heap = priority_queue<T, vector<T>, greater<T>>;
template<typename T, size_t N> istream& operator>>(istream& is, array<T, N>& arr) { for (size_t i = 0; i < N; i++) { is >> arr[i]; } return is; }
template<typename T, size_t N> istream& operator>>(istream& is, vector<array<T, N>>& vec) { for (auto &arr : vec) { is >> arr; } return is; }
template<typename T1, typename T2> istream &operator>>(istream& in, pair<T1, T2>& input) { return in >> input.ff >> input.ss; }
template<typename T> istream &operator>>(istream &in, vector<T> &v) { for (auto &el : v) in >> el; return in; }
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
const static ll INF = 4e18 + 10;
const static int inf = 1e9 + 100;
const static int MX = 1e5 + 5;
struct EulerianPath {
int nodes, edges;
bool directed;
vvpii graph;
vi deg, indeg, outdeg;
vt<bool> used;
vi ans_edges, ans_nodes;
EulerianPath(int _nodes, bool _directed = false)
: nodes(_nodes), edges(0), directed(_directed), graph(_nodes) {
if(directed) indeg.assign(nodes,0), outdeg.assign(nodes,0);
else deg.assign(nodes,0);
}
void add_edge(int u, int v, int id) {
graph[u].emplace_back(v, id);
edges++;
if(directed) {
outdeg[u]++;
indeg[v]++;
} else {
graph[v].emplace_back(u, id);
deg[u]++;
deg[v]++;
}
}
int find_start() const {
int start = -1;
if(!directed) {
int odd = 0;
for(int i = 0; i < nodes; i++) {
if(deg[i] & 1) {
odd++;
start = i;
}
if(start < 0 && deg[i] > 0) start = i;
}
if(start < 0) return 0;
if(odd != 0 && odd != 2) return -1;
} else {
int plus1 = 0, minus1 = 0;
for(int i = 0; i < nodes; i++) {
int d = outdeg[i] - indeg[i];
if(d == 1) { plus1++; start = i; }
else if(d == -1) minus1++;
else if(d != 0) return -1;
if(start < 0 && outdeg[i] > 0) start = i;
}
if(start < 0) return 0;
if(!((plus1 == 1 && minus1 == 1) || (plus1 == 0 && minus1 == 0))) return -1;
}
return start;
}
void dfs(int u) {
if(used.empty()) {
used.rsz(edges);
}
while(!graph[u].empty()) {
auto [v, id] = graph[u].back();
graph[u].pop_back();
while((int)used.size() <= id) used.pb(0);
if(used[id]) continue;
used[id] = true;
dfs(v);
ans_edges.pb(id);
}
ans_nodes.pb(u);
}
pair<vi, vi> get_path() {
int start = find_start();
if(start < 0) return {};
used.rsz(edges);
dfs(start);
if((int)ans_edges.size() != edges) return {};
rev(ans_nodes);
rev(ans_edges);
return {ans_nodes, ans_edges};
}
vi get_any_cycle() {
int start = -1;
for(int i = 0; i < nodes; i++) {
if(!graph[i].empty()) {
start = i;
break;
}
}
if(start == -1) return {}; // no edges
vi cycle;
stack<int> st;
st.push(start);
while(!st.empty()) {
int u = st.top();
if(graph[u].empty()) {
cycle.push_back(u);
st.pop();
} else {
auto [v, id] = graph[u].back();
graph[u].pop_back();
if((int)used.size() <= id) used.rsz(id + 1);
if(used[id]) continue;
used[id] = true;
st.push(v);
}
}
reverse(all(cycle)); // optional, to start from the first vertex
return cycle;
}
};
void solve() {
int n, m; cin >> n >> m;
EulerianPath graph(n);
for(int i = 0; i < m; i++) {
int u, v; cin >> u >> v;
u--, v--;
graph.add_edge(u, v, i);
}
auto ans = graph.get_any_cycle();
ans.pop_back();
for(auto& x : ans) {
cout << x + 1 << ' ';
}
cout << '\n';
}
signed main() {
IOS;
startClock
int t = 1;
//cin >> t;
for(int i = 1; i <= t; i++) {
//cout << "Case #" << i << ": ";
solve();
}
endClock;
printMemoryUsage();
return 0;
}
