#include <bits/stdc++.h>
using namespace std;
/*{{{*/  //template
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
constexpr int INF = numeric_limits<int>::max()/2;
constexpr long long LINF = numeric_limits<long long>::max()/3;
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define sz(x) (int)(x).size()
#define debug(x) cerr<<#x<<":"<<x<<endl
#define debug2(x,y) cerr<<#x<<","<<#y":"<<x<<","<<y<<endl
//struct fin{ fin(){ cin.tie(0); ios::sync_with_stdio(false); } } fin_;
struct Double{ double d; explicit Double(double x) : d(x){} };
ostream& operator<<(ostream& os,const Double x){ os << fixed << setprecision(20) << x.d; return os; }
template<typename T> ostream& operator<<(ostream& os,const vector<T>& vec){ os << "["; for(const auto& v : vec){ os << v << ","; } os << "]"; return os; }
template<typename T,typename U> ostream& operator<<(ostream& os, const map<T,U>& mp){ os << "{"; for(auto& p : mp){ os << p << ","; } os << "}"; return os; }
template<typename T,typename U> ostream& operator<<(ostream& os,const pair<T,U>& p){ os << "(" << p.first << ","<< p.second <<")"; return os; }
template<typename T> ostream& operator<<(ostream& os,const set<T>& st){ os<<"{"; for(T v:st) os<<v<<","; os <<"}"; return os; }
template<typename T,typename U> inline void chmax(T &x,U y){ if(y>x) x = y; }
template<typename T,typename U> inline void chmin(T &x,U y){ if(y<x) x = y; }
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
ll gcd(ll a,ll b){ if(b==0) return a; else return gcd(b,a%b); }
//constexpr double eps = 1e-14; 
constexpr double eps = 1e-10; 
constexpr ll mod = 1e9+7;
const int dx[]={1,0,-1,0} ,dy[] = {0,1,0,-1};
/*}}}*/

struct MinCostFlow{/*{{{*/
    const int inf = std::numeric_limits<int>::max()/2;
    struct edge{
        int to,cap,cost,rev;
        edge(){}
        edge(int t,int ca,int co,int r) : to(t),cap(ca),cost(co),rev(r){}
    };

    int V;  // # of node 
    vector<vector<edge>> G;
    MinCostFlow(){}
    MinCostFlow(int V_){ init(V_); }

    void init(int V_){
        V = V_;
        G.resize(V);
    }

    void add_edge(int from,int to,int cap,int cost){
        G[from].emplace_back(to,cap,cost,G[to].size());
        G[to].emplace_back(from,0,-cost,G[from].size()-1);
    }

    // s->tに向かって流量f流すときの最小費用
    // もしs->tに向かってf流せない場合は-1
    int min_cost_flow(int s,int t,int f){
        int res=0;
        vector<int> dist(V,inf);
        vector<int> prevv(V),preve(V);
        while(f>0){
            dist.assign(V,inf);
            dist[s] = 0;
            bool update=true;
            while(update){
                update=false;
                for(int v=0;v<V;v++){
                    if(dist[v]==inf) continue;
                    for(int i=0;i<(int)G[v].size();i++){
                        edge &e = G[v][i];
                        if(e.cap>0 and dist[e.to] > dist[v]+e.cost){
                            dist[e.to] = dist[v] + e.cost;
                            prevv[e.to] = v;
                            preve[e.to] = i;
                            update = true;
                        }
                    }
                }
            }

            if(dist[t] == inf) return inf;   // 流量fを流すことは不可能

            int d = f;
            for(int v=t;v!=s;v=prevv[v]) d = min(d,G[prevv[v]][preve[v]].cap);
            f -= d;
            res += d * dist[t];
            for(int v=t;v!=s;v=prevv[v]){
                edge &e = G[prevv[v]][preve[v]];
                e.cap -= d;
                G[v][e.rev].cap += d;
            }
        }
        return res;
    }
};/*}}}*/

bool ok(vector<int>& a,vector<int>& b){
    for(int i=0;i<(int)a.size();i++){
        if(a[i] <= b[i]) return false;
    }
    return true;
}


void solve(int N){
    vector<vector<int>> box(N,vector<int>(3,0));
    rep(i,N){
        rep(j,3) cin >> box[i][j];
        sort(all(box[i]));
    }

    MinCostFlow graph(2*N+2);
    int SOURCE = 2*N;
    int SINK = 2*N+1;

    rep(i,N) rep(j,N) {
        if(ok(box[i],box[j])){
            int t = -1;
            rep(k,3) t *= box[j][k];
            graph.add_edge(i,j+N,1,t);
        }
    }
    rep(i,N){
        graph.add_edge(i,SINK,1,0);
        graph.add_edge(SOURCE,i,1,0);
        graph.add_edge(i+N,SINK,1,0);
    }


    int t = graph.min_cost_flow(SOURCE,SINK,N);
    int sum = 0;
    for(int i=0;i<N;i++) sum += box[i][0] * box[i][1] * box[i][2];
    cout << sum + t << endl;
}

int main(){
    while(1){
        int N; cin >> N;
        if(N == 0)break;
        solve(N);
    }
}



Measured memory_bytes: 3264