#include "bits/stdc++.h"
using namespace std;
int n;
vector<vector<int>> ed;
void Init(int N_) {
n = N_;
ed.resize(n);
}
void Link(int A, int B) {
ed[A].push_back(B);
ed[B].push_back(A);
}
bool dfs(int cur, int pr, int crt, vector<bool>& visited){
visited[cur] = true;
for (auto to : ed[cur]){
if (to == pr || to == crt) continue;
if (visited[to]) return false;
if (!dfs(to, cur, crt, visited)) return false;
}
return true;
}
int CountCritical() {
int cnt = 0;
for (int i = 0; i < n; ++i){
bool flag = true;
vector<bool> visited(n);
for (int j = 0; j < n; ++j) {
if (i == j || visited[j]) continue;
flag = flag & dfs(j, j, i, visited);
}
for (int j = 0; j < n; ++j){
if (i == j) continue;
int deg = 0;
for (auto to : ed[j]) {
if (to == i) continue;
deg++;
}
if (deg > 2) flag = false;
}
cnt += flag;
}
return cnt;
}
