#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const int MAXN = 2e5;
int M, N, ans;
struct Data
{
int a, b, c;
bool operator < (const Data& p) { return c<p.c; }
};
Data A[MAXN+10];
struct Node1
{
Node1() : val(0), lc(NULL), rc(NULL) {}
int val;
Node1 *lc, *rc;
};
Node1 *tree[MAXN+10];
void update1(Node1 *node, int tl, int tr, int pos, int val)
{
if(tl==tr)
{
node->val=val;
return;
}
int mid=tl+tr>>1;
if(pos<=mid)
{
if(node->lc==NULL) node->lc=new Node1;
update1(node->lc, tl, mid, pos, val);
}
else
{
if(node->rc==NULL) node->rc=new Node1;
update1(node->rc, mid+1, tr, pos, val);
}
node->val=0;
if(node->lc!=NULL) node->val=max(node->val, node->lc->val);
if(node->rc!=NULL) node->val=max(node->val, node->rc->val);
}
int query1(Node1 *node, int tl, int tr, int l, int r)
{
if(l<=tl && tr<=r) return node->val;
if(r<tl || tr<l) return 0;
int mid=tl+tr>>1;
int ret=0;
if(node->lc!=NULL) ret=max(ret, query1(node->lc, tl, mid, l, r));
if(node->rc!=NULL) ret=max(ret, query1(node->rc, mid+1, tr, l, r));
return ret;
}
void update2(int ypos, int xpos, int val) { for(int i=ypos; i<=N; i+=(i&-i)) update1(tree[i], 1, N, xpos, val); }
int query2(int ypos, int xpos) { int ret=0; for(int i=ypos; i>0; i-=(i&-i)) ret=max(ret, query1(tree[i], 1, N, 1, xpos)); return ret; }
int main()
{
int i, j;
scanf("%d%d", &M, &N);
for(i=1; i<=N; i++) tree[i]=new Node1();
vector<int> Va, Vb;
for(i=1; i<=N; i++) scanf("%d", &A[i].a), Va.push_back(A[i].a);
for(i=1; i<=N; i++) scanf("%d", &A[i].b), Vb.push_back(A[i].b);
if(M==3) for(i=1; i<=N; i++) scanf("%d", &A[i].c);
else for(i=1; i<=N; i++) A[i].c=A[i].a;
sort(Va.begin(), Va.end());
sort(Vb.begin(), Vb.end());
for(i=1; i<=N; i++) A[i].a=lower_bound(Va.begin(), Va.end(), A[i].a)-Va.begin()+1;
for(i=1; i<=N; i++) A[i].b=lower_bound(Vb.begin(), Vb.end(), A[i].b)-Vb.begin()+1;
sort(A+1, A+N+1);
for(i=1; i<=N; i++)
{
int now=query2(A[i].a, A[i].b)+1;
ans=max(ans, now);
update2(A[i].a, A[i].b, now);
}
printf("%d", ans);
}
