#include "friend.h"
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef vector<vector<int>> vii;
#define pb push_back
#define sz(a) (int)(a.size())
struct FlowEdge {
int v, u;
long long cap, flow = 0;
FlowEdge(int v, int u, long long cap) : v(v), u(u), cap(cap) {}
};
struct Dinic {
const long long flow_inf = 1e18;
vector<FlowEdge> edges;
vector<vector<int>> adj;
int n, m = 0;
int s, t;
vector<int> level, ptr;
queue<int> q;
Dinic(int n, int s, int t) : n(n), s(s), t(t) {
adj.resize(n);
level.resize(n);
ptr.resize(n);
}
void add_edge(int v, int u, long long cap) {
edges.emplace_back(v, u, cap);
edges.emplace_back(u, v, 0);
adj[v].push_back(m);
adj[u].push_back(m + 1);
m += 2;
}
bool bfs() {
while (!q.empty()) {
int v = q.front();
q.pop();
for (int id : adj[v]) {
if (edges[id].cap - edges[id].flow < 1)
continue;
if (level[edges[id].u] != -1)
continue;
level[edges[id].u] = level[v] + 1;
q.push(edges[id].u);
}
}
return level[t] != -1;
}
long long dfs(int v, long long pushed) {
if (pushed == 0)
return 0;
if (v == t)
return pushed;
for (int& cid = ptr[v]; cid < (int)adj[v].size(); cid++) {
int id = adj[v][cid];
int u = edges[id].u;
if (level[v] + 1 != level[u] || edges[id].cap - edges[id].flow < 1)
continue;
long long tr = dfs(u, min(pushed, edges[id].cap - edges[id].flow));
if (tr == 0)
continue;
edges[id].flow += tr;
edges[id ^ 1].flow -= tr;
return tr;
}
return 0;
}
long long flow() {
long long f = 0;
while (true) {
fill(level.begin(), level.end(), -1);
level[s] = 0;
q.push(s);
if (!bfs())
break;
fill(ptr.begin(), ptr.end(), 0);
while (long long pushed = dfs(s, flow_inf)) {
f += pushed;
}
}
return f;
}
};
int e[1000][1000],c[1000],N;
bool vis[1000];
bool check =1;
void dfs(int v){
vis[v] = 1;
for(int i=0;i<N;i++){
if(e[v][i] && !vis[i]){
c[i] = c[v]^1;
dfs(i);
}
if(e[v][i] && vis[i] && c[i] == c[v])check = 0;
}
}
int findSample(int n,int confidence[],int h[],int protocol[]){
N=n;
int ans = 0;
bool sub4 = 1;
for(int i=1;i<n;i++){
if(protocol[i] == 2)sub4 = 0;
}
if(n<=10){
vector<set<int>>adj(n);
for(int i=1;i<n;i++){
if(!protocol[i]){
adj[i].insert(h[i]);
adj[h[i]].insert(i);
}else{
for(int x:adj[h[i]]){
adj[i].insert(x);
adj[x].insert(i);
}
}
if(protocol[i] == 2){
adj[i].insert(h[i]);
adj[h[i]].insert(i);
}
}
for(int i=0;i<(1<<n);i++){
vector<int>v;
int cost = 0;
for(int j=0;j<n;j++){
if(i&(1<<j)){
v.push_back(j);
cost+=confidence[j];
}
}
for(int x:v){
for(int y:v){
if(adj[x].count(y) || adj[y].count(x))cost = 0;
}
}
ans = max(ans,cost);
}
return ans;
}
if(sub4){
for(int i=1;i<n;i++){
if(!protocol[i])e[i][h[i]] = e[h[i]][i] = 1;
else{
for(int j=0;j<n;j++){
if(e[h[i]][j])e[i][j] = e[j][i] = 1;
}
}
}
Dinic d(2*n+2,2*n,2*n+1);
for(int i=0;i<n;i++){
if(!vis[i])dfs(i);
}
assert(check);
int ans = 0;
for(int i=0;i<n;i++){
int cnt = 0;
for(int j=0;j<n;j++)cnt+=e[i][j];
if(!cnt){
ans++;
continue;
}
if(!c[i]){
d.add_edge(2*n,i,1);
for(int j=0;j<n;j++){
if(e[i][j])d.add_edge(i,n+j,1);
}
}
else d.add_edge(n+i,2*n+1,1);
}
ans+=d.flow();
return ans;
}
return 0;
}
