#include "friend.h"
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pi pair<int, int>
#define pl pair<ll, ll>
#define vi vector<int>
#define vl vector<ll>
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(),(x).end()
/*const int maxn=10;
vector<vi> graph(maxn,vi(maxn,0));
int findSample(int n, int val[], int host[], int prot[]) {// sub1
for (int i=1; i<n; i++) {
if (prot[i]==0 || prot[i]==2) {
graph[i][host[i]]=1;
graph[host[i]][i]=1;
}
if (prot[i]) {
for (int j=0; j<n; j++) {
graph[i][j]|=graph[host[i]][j];
graph[j][i]|=graph[host[i]][j];
}
}
}
int mx=0;
for (int i=0; i<(1<<n); i++) {
bool ok=1;
for (int j=0; j<n && ok; j++) {
for (int k=j+1; k<n && ok; k++) {
if ((i&(1<<j)) && (i&(1<<k)) && graph[j][k]) {
ok=0;
}
}
}
if (ok) {
int cur=0;
for (int j=0; j<n; j++) {
if (i&(1<<j)) {
cur+=val[j];
}
}
mx=max(mx,cur);
}
}
return mx;
}*/
/*int findSample(int n, int val[], int host[], int prot[]) {// sub2
return accumulate(val,val+n,0);
}*/
/*int findSample(int n, int val[], int host[], int prot[]) {// sub3
return *max_element(val,val+n);
}*/
/*const int maxn=1010;
vector<vi> graph(maxn);
vector<pi> dp(maxn,pi({0,0}));
void dfs(int cur, int prev=-1) {
for (auto to:graph[cur]) {
if (to==prev) {
continue;
}
dfs(to,cur);
dp[cur].fi+=dp[to].se;
dp[cur].se+=max(dp[to].fi,dp[to].se);
}
}
int findSample(int n, int val[], int host[], int prot[]) {// sub4
for (int i=0; i<n; i++) {
dp[i].fi=val[i];
}
for (int i=1; i<n; i++) {
graph[i].pb(host[i]);
graph[host[i]].pb(i);
}
dfs(0);
return max(dp[0].fi,dp[0].se);
}*/
const int maxn=1010;
vector<vi> graph(maxn);
vi seen(maxn,-1);
void dfs(int cur, int mul=1) {
seen[cur]=mul;
for (auto to:graph[cur]) {
if (seen[to]!=-1) {
continue;
}
dfs(to,mul^1);
}
}
struct Dinic {
struct edge {
int u,v;
ll cap=0,flow=0;
edge(int _u, int _v, ll _cap): u(_u),v(_v),cap(_cap) {}
};
int m=0;
int n;
int s,t;
vector<edge> edges;
vector<vi> graph;
vi ptr,lvl;
queue<int> q;
Dinic(int _n, int _s, int _t): n(_n),s(_s),t(_t) {
graph.resize(n);
ptr.resize(n,0);
lvl.resize(n,-1);
}
int add(int u, int v, ll cap) {
edges.emplace_back(u,v,cap);
edges.emplace_back(v,u,0);
graph[u].pb(m++);
graph[v].pb(m++);
return m-2;
}
bool bfs() {
while (q.size()) {
int a=q.front();
q.pop();
for (auto to:graph[a]) {
if (lvl[edges[to].v]==-1 && edges[to].cap-edges[to].flow) {
q.push(edges[to].v);
lvl[edges[to].v]=lvl[a]+1;
}
}
}
return lvl[t]!=-1;
}
ll dfs(int cur, ll push) {
if (cur==t || push==0) {
return push;
}
for (int& pt=ptr[cur]; pt<graph[cur].size(); pt++) {
int to=edges[graph[cur][pt]].v;
if (lvl[to]!=lvl[cur]+1) {
continue;
}
ll p=dfs(to,min(push,edges[graph[cur][pt]].cap-edges[graph[cur][pt]].flow));
if (p) {
edges[graph[cur][pt]].flow+=p;
edges[graph[cur][pt]^1].flow-=p;
return p;
}
}
return 0;
}
ll flow() {
ll f=0;
while (1) {
fill(all(lvl),-1);
lvl[s]=0;
q.push(s);
if (!bfs()) {
break;
}
fill(all(ptr),0);
while (ll p=dfs(s,1e18)) {
f+=p;
}
}
return f;
}
};
int findSample(int n, int val[], int host[], int prot[]) {// sub5
for (int i=1; i<n; i++) {
if (prot[i]==0) {
graph[i].pb(host[i]);
graph[host[i]].pb(i);
}
else {
for (auto a:graph[host[i]]) {
graph[a].pb(i);
graph[i].pb(a);
}
}
}
for (int i=0; i<n; i++) {
if (seen[i]==-1) {
dfs(i);
}
}
Dinic data(n+2,n,n+1);
for (int i=0; i<n; i++) {
if (seen[i]) {
data.add(n,i,1);
for (auto to:graph[i]) {
data.add(i,to,n);
}
}
else {
data.add(i,n+1,1);
}
}
return n-data.flow();
}
