#include <bits/stdc++.h>
#include <variant>
using namespace std;
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x << ' '; print(x); cerr << endl;
#else
#define dbg(x)
#endif
void print(int x) {cerr << x;}
void print(long long x) {cerr << x;}
void print(char x) {cerr << x;}
void print(string x) {cerr << x;}
void print(double x) {cerr << x;}
template <class T> void print(vector <T> x);
template <class T> void print(set <T> x);
template <class T> void print(multiset <T> x);
template <class T, class V> void print(pair <T, V> x);
template <class T, class V> void print(map <T, V> x);
template <class T> void print(vector <T> x) {cerr << "[ "; for(auto i : x) {print(i); cerr << ' ';} cerr << "]";}
template <class T> void print(set <T> x) {cerr << "[ "; for(auto i : x) {print(i); cerr << ' ';} cerr << "]";}
template <class T> void print(multiset <T> x) {cerr << "[ "; for(auto i : x) {print(i); cerr << ' ';} cerr << "]";}
template <class T, class V> void print(pair <T, V> x) {cerr << "{"; print(x.first); cerr << ' '; print(x.second); cerr << "}";}
template <class T, class V> void print(map <T, V> x) {cerr << "[ "; for(auto i : x) {print(i); cerr << ' ';} cerr << "]";}
#define ll long long
#define pb push_back
#define ppb pop_back
#define PII pair <int, int>
#define PLL pair <ll, ll>
#define all(v) (v).begin(), (v).end()
#define OK cerr << "OK\n";
#define MP make_pair
const int N0 = 1005, M0 = 2e5 + 5;
int n, m;
vector <int> G[N0];
bool visited[N0];
bool dfs(int node, int parent){
bool cycle = 0;
visited[node] = 1;
for(int u : G[node]){
if(u == parent) continue;
if(visited[u]) cycle = 1;
else cycle |= dfs(u, node);
}
return cycle;
}
variant <bool, vector <int>> find_journey(int N, int M, vector<int> U, vector<int> V){
for(int i = 0; i < M; i++){
G[U[i]].pb(V[i]);
}
return dfs(0, -1);
}
