#include "september.h"
#include <bits/stdc++.h>
using namespace std;
vector<vector<int>> ch;
vector<vector<vector<int>>> d;
vector<int> p, ind;
vector<bool> vis, passed;
queue<int> q;
void dfs(int node){
vis[node] = true;
for(int i : ch[node]){
if(!vis[i]) dfs(i);
}
q.push(node);
}
int solve(int N, int M, vector<int> F, vector<vector<int>> S) {
ch.clear(), ch.resize(N);
d.clear(), d.resize(M);
p.clear(), p.assign(M, 0);
ind.clear(), ind.assign(M, 0);
int k, maxk = 0, ans = 0;
for(int i = 1; i < N; ++i){
ch[F[i]].push_back(i);
}
for(int i = 0; i < M; ++i){
k = 0;
d[i].resize(N);
vis.assign(N, false);
passed.assign(N, false);
for(int j = 0; j < N-1; ++j){
passed[S[i][j]] = true;
if(!vis[S[i][j]]) dfs(S[i][j]);
while(!q.empty() && passed[q.front()]){
d[i][k].push_back(q.front());
q.pop();
}
if(q.empty()) k++;
}
maxk = max(k, maxk);
}
for(int i = 0; i < maxk; ++i){
for(int j = 0; j < M; ++j){
for(int l : d[j][i]){
p[j] += l;
ind[j]++;
}
}
bool s = true;
int tmp = p[0], tmi = ind[0];
for(int j = 1; j < M; ++j){
if(tmp != p[j] || tmi != ind[j]) s = false;
}
if(s) ans++;
}
return ans;
}
