#include <bits/stdc++.h>
#define mp make_pair
#define all(a) a.begin(),a.end()
#define X first
#define Y second
using namespace std;
using pii = pair <long long, long long>;
constexpr int maxn = 2e5 + 10;
constexpr int mod = 1000002022;
constexpr long long inf = 1e17 + 10;
int n, m;
vector <pii> graph [maxn];
vector <int> start = {};
int ver = -1;
int ans[4];
inline void dfs (int v, int par = -1) {
int sz = (int) graph[v].size ();
if (par > -1) --sz;
if (sz <= 1) {
for (pii i : graph[v]) if ((i.Y ^ 1) != par) {
start.push_back (i.Y);
dfs (i.X, i.Y);
return;
}
return;
}
ver = 0;
ans[0] = graph[v][0].Y;
ans[2] = graph[v][1].Y;
if ((graph[v][0].Y ^ 1) == par) ans[0] = graph[v][2].Y;
else if ((graph[v][1].Y ^ 1) == par) ans[2] = graph[v][2].Y;
ans[1] = (ans[0] ^ 1);
ans[3] = (ans[2] ^ 1);
}
variant <bool, vector <int>> find_journey (int N, int M, vector <int> U, vector <int> V) {
n = N, m = M;
for (int i = 0; i < m; ++i) {
graph[U[i]].push_back (mp (V[i], i));
}
dfs (0);
if (ver == -1) {
return false;
}
vector <int> res = {};
for (int i : start) res.push_back (i);
res.push_back (ans[0]);
res.push_back (ans[1]);
res.push_back (ans[2]);
res.push_back (ans[3]);
res.push_back (ans[1]);
res.push_back (ans[0]);
res.push_back (ans[3]);
res.push_back (ans[2]);
reverse (all (start));
for (int i : start) res.push_back (i);
return res;
}
