#include "islands.h"
#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define fr first
#define sc second
const int maxn = 2e5+10;
int n, m, tin[maxn], low[maxn], mark[maxn], iscyc[maxn], can0[maxn], timer;
vector<int> g[maxn], gt[maxn];
map<int,vector<int>> boats[maxn];
vector<int> cur, final;
int cycbeg = -1;
void dfs(int u, int ant) {
mark[u] = 1;
cur.pb(u);
if(final.size()) return;
for(auto v : g[u]) if(v != ant) {
if(final.size()) return;
if(mark[v]) {
final = cur;
cycbeg = v;
return;
}
else dfs(v,u);
}
}
void dfs0(int u) {
can0[u] = 1;
for(auto v : g[u]) {
if(can0[v] == 0) dfs0(v);
}
}
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++) {
g[U[i]].pb(V[i]);
gt[V[i]].pb(U[i]);
boats[U[i]][V[i]].pb(i);
}
dfs(0,-1);
dfs0(0);
if(final.size()) {
return true;
}
for(int i = 0; i < n; i++) {
for(auto X : boats[i]) {
if(X.sc.size() > 1 && can0[i]) return true;
}
}
return false;
}
