#include <bits/stdc++.h>
using namespace std;
typedef int ll;
typedef tuple<ll, ll, ll> plll;
typedef vector<plll> vplll;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<pll> vpll;
typedef vector<vector<pll>> vvpll;
typedef vector<vector<ll>> vvll;
typedef vector<bool> vb;
typedef vector<vector<bool>> vvb;
#define loop(i, s, e) for (ll i = (s); i < (e); ++i)
#define loopr(i, e, s) for (ll i = (e)-1; i >= (s); --i)
#define all(a) a.begin(), a.end()
const ll inf = 1e9 + 7;
ll n;
vll par, sz, ed;
ll find(ll v) {
if (par[v] == v) return v;
return par[v] = find(par[v]);
}
void uni(ll a, ll b) {
ll x = find(a), y = find(b);
if (x==y) {
ed[x]++;
return;
}
if (sz[x]<sz[y]) swap(x,y);
sz[x]+=sz[y];
ed[x]+=ed[y]+1;
par[y] = x;
}
void Init(int N_) {
n= N_;
par.resize(n);
sz.resize(n,1);
ed.resize(n,0);
loop(i,0,n) par[i] = i;
}
void Link(int a, int b) {
uni(a,b);
}
int CountCritical() {
ll ans = 0;
vb vis(n);
loop(i,0,n) {
ll pari = find(i);
if (!vis[pari]) {
if (ed[pari] == sz[pari]-1) {
vis[pari] = 1;
ans++;
}
}
}
return ans;
}
