#include using namespace std; #define rep(i,n) for(ll i=0;i=0;i--) #define perl(i,r,l) for(ll i=r-1;i>=l;i--) #define fi first #define se second #define pb push_back #define ins insert #define pqueue(x) priority_queue,greater> #define all(x) (x).begin(),(x).end() #define CST(x) cout<> #define rev(x) reverse(x); using ll=long long; using vl=vector; using vvl=vector>; using pl=pair; using vpl=vector; using vvpl=vector; const ll MOD=1000000007; const ll MOD9=998244353; const int inf=1e9+10; const ll INF=4e18; const ll dy[9]={0,1,-1,0,1,1,-1,-1,0}; const ll dx[9]={1,0,0,-1,1,-1,1,-1,0}; template inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; } vl topsort(vvl &g){ ll n=g.size(); vl ans,ind(n); rep(i,n)for(auto e:g[i])ind[e]++; queue que; rep(i,n)if(!ind[i])que.push(i); while(!que.empty()){ ll v=que.front();que.pop(); ans.pb(v); for(auto nv:g[v]){ ind[nv]--;if(!ind[nv])que.push(nv); } } return ans; } int main(){ ll n;cin >> n; vvl p(n,vl(3)); rep(i,n){ rep(j,3)cin >> p[i][j]; sort(all(p[i])); } vvl g(n); rep(i,n){ rep(j,n){ bool ok=true; rep(k,3)if(p[i][k]>=p[j][k])ok=false; if(ok)g[i].emplace_back(j); } } auto ts=topsort(g); //if(ts.size()!=n)cout << -1 << endl,exit(0); vl dp(n); for(auto p:ts){ for(auto to:g[p]){ chmax(dp[to],dp[p]+1); } } cout << *max_element(all(dp))+1 << endl; }