#include "september.h"
//ᴇᴀᴄʜ ᴘᴇʀꜱᴏɴ ᴡɪʟʟ ᴏɴʟʏ ʜᴀᴠᴇ ᴡʜᴀᴛ ᴛʜᴇʏ ᴇɴᴅᴇᴀᴠᴏᴜʀᴇᴅ ᴛᴏᴡᴀʀᴅꜱ [53:39]
//Author: Sazid Hasan
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef double dl;
typedef vector<int> vi;
typedef vector<vector<int>> vii;
typedef vector<ll> vl;
typedef vector<bool> vb;
typedef pair<int,int> pii;
typedef pair<ll, ll> pll;
#define ff first
#define ss second
#define all(a) a.begin(),a.end()
#define gcd(a,b) __gcd(a,b)
#define lcm(a,b) (a*(b/gcd(a,b)))
#define spc " "
#ifdef ONLINE_JUDGE
#define debarr(array)
#define deb(x)
#define del
#else
#define debarr(array) for(int w = 0; w < array.size(); w++) cerr << #array << "-" << w << " = " << array[w] << endl;
#define deb(x) cerr << #x << " = " << x << endl;
#define del cerr << '\n';
#endif
const double PI = acos(-1);
const int MOD = 1000000007;
const int inf = (2147483647);
int solve(int N, int M, std::vector<int> F, std::vector<std::vector<int>> S) {
vi till(N, -1);
for(auto x: S){
for(int i = 0; i < N-1; i++) till[x[i]] = max(till[x[i]], i);
}
vi deg(N, 0);
for(int i = 1; i < N; i++){
deg[F[i]]++;
}
queue<int> que;
for(int i = 0; i < N; i++){
if(deg[i]==0) que.push(i);
}
while(!que.empty()){
int ff = que.front(); que.pop();
if(ff==0) continue;
till[F[ff]] = max(till[F[ff]], till[ff]);
deg[F[ff]]--;
if(deg[F[ff]]==0) que.push(F[ff]);
}
int ptr = 0;
int cnt = 0;
while(ptr < N-1){
int now = ptr;
while (now<=ptr)
{
for(int i = 0; i < M; i++){
ptr = max(ptr, till[S[i][now]]);
}
now++;
}
ptr++, cnt++;
}
return cnt;
}
