#include <bits/stdc++.h>
using namespace std;
vector<vector<int>> create_map(int n, int m, vector<int> a, vector<int> b) {
vector<vector<pair<int, int>>> g(n);
for (int i = 0; i < m; i++) {
g[--a[i]].push_back({--b[i], i});
g[b[i]].push_back({a[i], i});
}
vector<int> e, id(n);
vector<bool> vis(n), done(m);
vector<vector<int>> bk(n);
int t = 0;
auto dfs = [&](const auto &dfs, int u) -> void {
e.push_back(u);
id[u] = e.size();
e.push_back(u);
e.push_back(u);
vis[u] = 1;
for (auto [v, i] : g[u]) {
if (!vis[v]) {
dfs(dfs, v);
done[i] = 1;
e.push_back(u);
}
}
};
dfs(dfs, 0);
for (int &x : e) {
++x;
}
for (int i = 0; i < m; i++) {
if (!done[i]) {
bk[a[i]].push_back(b[i]);
}
}
vector<vector<int>> gg(4 * n - 1, e);
for (int i = 0; i < n; i++) {
for (int j = 0, k = 0; k < bk[i].size(); j += 2, k++) {
gg[j][id[i]] = bk[i][k] + 1;
}
}
return gg;
}
