This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#define ll long long
#define eps 1e-7
#define all(x) ((x).begin()),((x).end())
#define usecppio ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
using namespace std;
using pii = pair<int, int>;
void solve_2();
int m, n;
int arr[3][202020];
set <int> s;
const int MAXR = 1000000007;
const int MAXC = 1000000007;
// max-dynamic-2seg
// msg555 impl, some modifications
int agg(int a, int b) {return max(a, b);}
struct Dynamic2DSeg
{
    struct Node
    {
        Node (int l, int r, int v = 0) : l(l), r(r), v(v), lc(NULL), rc(NULL){}
        int l, r, v;
        Node *lc, *rc;
    };
    struct RowNode
    {
        RowNode () : lc(NULL), rc(NULL), rowRoot(0, MAXC){}
        Node rowRoot;
        RowNode *lc, *rc;
    };
    RowNode root;
    static void update2(Node *node, int idx, int dt)
    {
        int lo = node -> l;
        int hi = node -> r;
        int mid = (lo + hi) / 2;
        if (lo + 1 == hi)
        {
            node -> v = dt;
            return;
        }
        Node *& next = idx < mid ? node -> lc : node -> rc;
        if (next == NULL)
            next = new Node(idx, idx + 1, dt);
        else if (next -> l <= idx && idx <= next -> r)
            update2(next, idx, dt);
        else
        {
            do {
                (idx < mid ? hi : lo) = mid;
                mid = (lo + hi) / 2;
            } while ((idx < mid) == (next->l < mid));
            Node * nnode = new Node(lo, hi);
            (next->l < mid ? nnode->lc : nnode->rc) = next;
            next = nnode;
            update2(nnode, idx, dt);
        }
        node -> v = agg(node->lc?node->lc->v:0, node->rc?node->rc->v:0);
    }
    static void update1(RowNode * node, int lo, int hi, int ridx, int idx, int dt)
    {
        int mid = (lo + hi) / 2;
        if (lo + 1 == hi)
            update2(&node -> rowRoot, idx, dt);
        else
        {
            RowNode *& nnode = ridx < mid ? node -> lc : node -> rc;
            (ridx < mid ? hi : lo) = mid;
            if (nnode == NULL)
                nnode = new RowNode();
            update1(nnode, lo, hi, ridx, idx, dt);
            dt = agg(node->lc ? query2(&node->lc->rowRoot, idx, idx + 1) : 0,
                     node->rc ? query2(&node->rc->rowRoot, idx, idx + 1) : 0);
            update2(&node->rowRoot, idx, dt);
        }
    }
    static int query2(Node *node, int a, int b)
    {
        if (node == NULL || b <= node -> l || node -> r <= a)
            return 0;
        else if (a <= node -> l && node -> r <= b)
            return node -> v;
        return agg(query2(node->lc, a, b), query2(node->rc, a, b));
    }
    static int query1(RowNode *node, int lo, int hi, int a1, int b1, int a2, int b2)
    {
        if (node == NULL || b1 <= lo || hi <= a1)
            return 0;
        else if (a1 <= lo && hi <= b1)
            return query2(&node->rowRoot, a2, b2);
        int mid = (lo + hi) / 2;
        return agg(query1(node->lc, lo, mid, a1, b1, a2, b2),
                   query1(node->rc, mid, hi, a1, b1, a2, b2));
    }
    void update(int x, int y, int dt)
    {
        update1(&root, 0, MAXR, x, y, dt);
    }
    int query(int x1, int y1, int x2, int y2)
    {
        return query1(&root, 0, MAXR, x1, x2 + 1, y1, y2 + 1);
    }
} DSEG;
void solve_3()
{
    vector <pair<int, pii>> v;
    for (int i = 0; i < n; i++)
        v.push_back({arr[0][i], {arr[1][i], arr[2][i]}});
    sort(all(v));
    vector <int> ans(n, 0);
    for (int i = n; i >= 0; i--)
    {
        int cx = v[i].second.first;
        int cy = v[i].second.second;
        ans[i] = DSEG.query(cx+1, cy+1, 1e9+1, 1e9+1) + 1;
        DSEG.update(cx, cy, ans[i]);
    }
    int r = 0;
    for (auto it:ans)
        r = max(it, r);
    cout << r << '\n';
}
int32_t main()
{
    usecppio
    cin >> m >> n;
    for (int i = 0; i < m; i++)
        for (int j = 0; j < n; j++)
            cin >> arr[i][j];
    if (m == 2)
        solve_2();
    else solve_3();
}
void solve_2()
{
    vector <pii> v;
    for (int i = 0; i < n; i++)
        v.push_back({arr[0][i], arr[1][i]});
    sort(all(v));
    vector <int> vv;
    for (int i = 0; i < n; i++)
        vv.push_back(v[i].second);
    set <int> :: iterator it;
    for (int i = 0; i < n; i++)
    {
        s.insert(vv[i]);
        it = s.upper_bound(vv[i]);
        if (it != s.end())
            s.erase(it);
    }
    cout << s.size() << '\n';
}
Compilation message (stderr)
matrix.cpp: In constructor 'Dynamic2DSeg::RowNode::RowNode()':
matrix.cpp:33:23: warning: 'Dynamic2DSeg::RowNode::rc' will be initialized after [-Wreorder]
   33 |         RowNode *lc, *rc;
      |                       ^~
matrix.cpp:32:14: warning:   'Dynamic2DSeg::Node Dynamic2DSeg::RowNode::rowRoot' [-Wreorder]
   32 |         Node rowRoot;
      |              ^~~~~~~
matrix.cpp:31:9: warning:   when initialized here [-Wreorder]
   31 |         RowNode () : lc(NULL), rc(NULL), rowRoot(0, MAXC){}
      |         ^~~~~~~| # | Verdict  | Execution time | Memory | Grader output | 
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