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

using i64 = long long;

int main() {
    cin.tie(nullptr)->sync_with_stdio(false);

    auto solve = [&]() {
        int n, m;
        cin >> n >> m;

        vector<vector<int>> g(n);
        for (int i = 0; i < m; i++) {
            int u, v;
            cin >> u >> v;
            u--, v--;
            g[u].push_back(v);
            g[v].push_back(u);
        }

        for (auto &v : g) {
            sort(v.begin(), v.end());
        }

        auto has = [&](int u, int v) {
            return binary_search(g[u].begin(), g[u].end(), v);
        };

        vector<int> nxt(n, -1), prv(n, -1);
        int cur = 0, tail = 0;

        for (int i = 1; i < n; i++) {
            if (nxt[cur] != -1 && prv[cur] != -1) {
                assert(has(cur, nxt[cur]) != has(cur, prv[cur]));
            }
            if (nxt[cur] == -1) {
                prv[i] = cur;
                tail = i;
                if (prv[cur] == -1 || has(cur, prv[cur]) == has(i, cur)) {
                    cur = i;
                }
            } else if (bool f = has(cur, prv[cur]); has(i, cur) == f) {
                prv[i] = cur;
                nxt[i] = nxt[cur];
                cur = i;
                if (has(i, nxt[cur]) == f) {
                    cur = nxt[cur];
                }
            } else {
                nxt[i] = cur;
                prv[i] = prv[cur];
                cur = i;
                if (has(i, prv[cur]) != f) {
                    cur = prv[cur];
                    if (prv[cur] == -1) {
                        cur = tail;
                    }
                }
            }

            if (prv[i] != -1) {
                nxt[prv[i]] = i;
            }
            if (nxt[i] != -1) {
                prv[nxt[i]] = i;
            }
        }

        for (int i = 0; i != -1; i = nxt[i]) {
            cout << i + 1 << " \n"[nxt[i] == -1];
        }
    };
    
    solve();
    
    return 0;
}