#include <algorithm>
#include <cfloat>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <memory>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <vector>
 
using namespace std;
 
typedef long long ll;
 
#define sz size()
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(c) (c).begin(), (c).end()
#define rep(i,a,b) for(ll i=(a);i<(b);++i)
#define per(i,a,b) for(ll i=(b-1);i>=(a);--i)
#define clr(a, b) memset((a), (b) ,sizeof(a))
#define ctos(c) string(1,c)
#define print(x) cout<<#x<<" = "<<x<<endl;
 
#define MOD 1000000007

vector<vector<ll> > vv;
ll d[1010];

void dfs(ll p, ll c){
  if(d[p]<c){
    d[p] = c;
  }
  else{
    return;
  }
  rep(i,0,vv[p].sz){
    dfs(vv[p][i],c+1);
  }
}

int main(){
  ll n;
  cin>>n;
  vector<ll> vx;
  vector<ll> vy;
  vector<ll> vz;
  rep(i,0,n){
    ll a,b,c;
    cin>>a>>b>>c;
    vx.pb(a);
    vy.pb(b);
    vz.pb(c);
  }
  vector<vector<ll> > vv_(n+2,vector<ll>());
  vv = vv_;
  rep(i,0,n){
    rep(j,0,n){
      if(i==j)continue;
      if(vx[i]<vx[j]&&vy[i]<vy[j]&&vz[i]<vz[j]){
        vv[i+1].pb(j+1);
      }
      else if(vx[i]<vx[j]&&vy[i]<vz[j]&&vz[i]<vy[j]){
        vv[i+1].pb(j+1);
      }
      else if(vx[i]<vy[j]&&vy[i]<vx[j]&&vz[i]<vz[j]){
        vv[i+1].pb(j+1);
      }
      else if(vx[i]<vy[j]&&vy[i]<vz[j]&&vz[i]<vx[j]){
        vv[i+1].pb(j+1);
      }
      else if(vx[i]<vz[j]&&vy[i]<vx[j]&&vz[i]<vy[j]){
        vv[i+1].pb(j+1);
      }
      else if(vx[i]<vz[j]&&vy[i]<vy[j]&&vz[i]<vx[j]){
        vv[i+1].pb(j+1);
      }
    }
  }
  rep(i,0,n){
    vv[0].pb(i+1);
  }
  rep(i,0,n){
    vv[i+1].pb(n+1);
  }
  clr(d,0);
  dfs(0,1);
  cout << d[n+1]-2 << endl;
  return 0;
}