Detecting cycle using DFS

/*
I am Hunting High and Low
Diving from the sky above
Looking for, more and more, once again
I'm Hunting High and Low
Sometimes I may win, sometimes I'll lose
It's just a game that I play

After the storm there's a calm
Through the clouds shines a ray of the sun
I'm carried from all my harm
There is no one I can't outrun

Now I'm leaving my worries behind
Feel the freedom of body and mind
I'm starting my journey, I'm drifting away with the wind, I go___________________:-
*/

#include <bits/stdc++.h>
using namespace std;
/*  #include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,
tree_order_statistics_node_update> indexed_set;  */

typedef long long  ll;
typedef unsigned long long ull;
typedef long double ld;
typedef pair < int , int > pi;
typedef pair < int64_t , int64_t > pii;
const int N = 1e5+7;

int luck[N], vis[N];
const int32_t mod = 1e9 + 7;


#define pb(x) push_back(x)
#define A(s)  s.begin(),s.end()
#define L(x)  (int)((x).size())
#define V     vector<int>
#define VL    vector<ll>
#define S     set<int>
#define SL    set<ll>
#define Ml    multiset < int >
#define ML    multiset < ll >
#define f(i,p,n) for(int i=(p);i<n;i++)
#define B(v)   v.begin()
#define E(v)   v.end()
#define M      map < int , int >
#define SS      second
#define F       first
vector < V > v(N);

template <class T>  inline void smax(T &x,T y){ x = max((x), (y));}
template <class T>  inline void smin(T &x,T y){ x = min((x), (y));}
void initializer(int n, int x = 1){
    if(x > n)return;
    luck[x] = 100;
    initializer(n, x + 1);
}
int flag = 0;
// to detect a cycle using dfs
void Eminem_Lover(int to_p, int check){
    vis[to_p] = true;
            for(auto it : v[to_p]){
            if(!vis[it]){
                Eminem_Lover(it, to_p);
            }
            else if(vis[it] && it != check)flag = 1;//Cycle detected
        }// check ki condition mandatory h ........... otherwise Jaha se call aayi h usi ko manke cycle bataa dega
}

ll expo(ll x, ll n, ll mod){
    ll res = 1LL;
    while(n){
	if(n & 1)   res = (res * x) % mod;
	   x = (x * x) % mod;
	   n = n / 2;
    }
    return res;
}
int main(){
   ios_base::sync_with_stdio(0);cin.tie(NULL);cout.tie(NULL);
   #ifndef ONLINE_JUDGE
//    freopen("in.txt", "r", stdin);
  //  freopen("out.txt", "w", stdout);
   #endif
   int i, j, k, l, r, cnt1 = 0, cnt2 = 0;
// Begin:-
    int n;
    cin >> n;

    f(i,0,n-1)cin >> l >> r, v[l].pb(r), v[r].pb(l);
    initializer(n);
    Eminem_Lover(3, 3);// Kisi b root ki adjacancy list me vahi element to present hoga nahi
    // isliye for first time Root ko hi check banaa k bhej diya h
    // Ho skta h glt ho logic.............. mgr lg to theek hi rha h
  cout << flag;







  	return 0;
}