#include <bits/stdc++.h>
#define pb push_back
#include "islands.h"
using namespace std;
constexpr static int MXN = 1e5 + 5;
int n, m;
vector<int> u, v;
vector<int> g[MXN];
int state[MXN];
bool dfs(int node)
{
state[node] = 1;
for (int c : g[node])
{
if (state[c] == 1)
return true;
if (state[c] == 0 && dfs(c))
return true;
}
state[node] = 2;
return false;
}
variant<bool, vector<int>> find_journey(int N, int M, vector<int> U, vector<int> V)
{
n = N, m = M;
u = U, v = V;
for (int i = 0; i < m; i++)
{
g[u[i]].pb(v[i]);
g[v[i]].pb(u[i]);
}
return dfs(0);
}
