//
#ifndef __SIZEOF_INT128__
#define __SIZEOF_INT128__
#endif
#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace chrono;
using namespace __gnu_pbds;
template <typename T> using oset = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>;
#define rep(i, p, k) for(int i(p); i < (k); ++i)
#define per(i, p, k) for(int i(p); i > (k); --i)
#define sz(x) (int)(x).size()
#define sc static_cast
typedef long long ll;
typedef long double ld;
typedef unsigned int uint;
typedef unsigned long long ull;
typedef __int128_t lll;
//#define int ll
template <typename T = int> using par = std::pair <T, T>;
#define fi first
#define se second
#define test int _number_of_tests(in()); while(_number_of_tests--)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define pb emplace_back
struct Timer {
string name{""};
time_point<high_resolution_clock> end, start{high_resolution_clock::now()};
duration<float, std::milli> dur;
Timer() = default;
Timer(string nm): name(nm) {}
~Timer() {
end = high_resolution_clock::now(); dur= end - start;
cout << "@" << name << "> " << dur.count() << " ms" << '\n';
}
};
template <typename T = int> inline T in()
{
static T x;
std::cin >> x;
return x;
}
std::string yn(bool b)
{
if(b) return "YES\n";
else return "NO\n";
}
template <typename F, typename S> std::ostream& operator<<(std::ostream& out, const std::pair <F, S>& par);
template <typename T> std::ostream& operator<< (std::ostream& out, const std::vector <T>& wek)
{
for(const auto& i : wek)out << i << ' ';
return out;
}
template <typename F, typename S> std::ostream& operator<<(std::ostream& out, const std::pair <F, S>& par)
{
out << '{'<<par.first<<", "<<par.second<<"}";
return out;
}
#define show(x) cerr << #x << " = " << x << '\n';
constexpr int maxn = 1e5 + 3;
vector <pair <int, int>> graf[maxn];
vector <pair <int, int>> rgraf[maxn];
bool us[maxn];
int sto[maxn];
void del(int w){
if(us[w])return;
us[w] = 1;
for(auto [i, j]: rgraf[w])if(!--sto[i])del(i);
}
variant <bool, vector <int>> find_journey(int n, int m, vector <int> u, vector <int> v){
rep(i, 0, m){
graf[u[i]].pb(v[i], i);
rgraf[v[i]].pb(u[i], i);
}
rep(i, 0, n)sto[i] = sz(graf[i]);
int s(0);
vector <int> ds;
rep(i, 0, n)if(!sto[i])del(i);
while(!us[s] && sto[s] == 1){
del(s);
for(auto [i, j]: graf[s])if(!us[i]){
ds.pb(j);
s = i;
break;
}
}
// cerr << s << '\n';
// rep(i, 0, n)cerr << us[i];
// cerr << '\n';
if(us[s])return false;
return true;
}
