#include <bits/stdc++.h>
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
#define FORR(i,a,b) for (int i=(a);i>=(b);i--)
#define pb push_back

using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef set<int> si;
typedef pair<int, pii> ti;
const int inf = 1e9;
const int mod = 1e9+7;

bool comp(const ti& l, const ti& r) {
  return (l.first < r.first && l.second.first < r.second.first && l.second.second < r.second.second);
}
ti a[1003];
int dp[1003];
main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  int x[3];
  FOR(i, 0, n){
    FOR(i, 0, 3)cin >> x[i];
    sort(x, x+3);
    a[i] = ti(x[0], pii(x[1], x[2]));
  }
  a[n] = ti(inf, pii(inf, inf));
  sort(a, a + n+1);
  FOR(i, 0, n+1){
    int ma = 0;
    FOR(j, 0, i){
      if(comp(a[j], a[i])){
        ma = max(ma, dp[j]);
      }
    }
    dp[i] = ma + 1;
  }
  cout << dp[n] - 1 << endl;
}