#include "september.h"
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<ll,ll,ll> ti;
typedef vector<ll> li;
typedef vector<li> lii;
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define LSOne(s) ((s)&(-s))
ll INF=1000000000000000010;
int inf=1e9+10;
ll M=1e9+7;
int solve(int n, int m, std::vector<int> p, std::vector<std::vector<int>> a) {
int ans=0,pos=0;
vi cnt(n,0);
REP(i,1,n)cnt[p[i]]++;
set<int> st,st2;
queue<int> q;
bool flag=1;
while(pos<n-1){
while(flag||st.size()!=pos){
flag=0;
REP(i,0,m){
int k=a[i][pos];
if(st.count(k))continue;
st.insert(k);
if(cnt[k]==0){
cnt[p[k]]--;
if(cnt[p[k]]==0)q.push(p[k]);
}
else st2.insert(k);
}
pos++;
}
while(!q.empty()){
int x=q.front();
q.pop();
if(st2.count(x)>0){
cnt[p[x]]--;
if(cnt[p[x]]==0)q.push(p[x]);
st2.erase(x);
}
}
if(st2.empty())ans++;
flag=1;
}
return ans;
}
