1 #include <cstdio>
 2 #include <vector>
 3 #include <algorithm>
 4 using namespace std;
 5 
 6 const int maxn=105;
 7 
 8 int f[maxn];
 9 int sf(int x){return x==f[x]?x:f[x]=sf(f[x]);}
10 
11 struct Edge {
12     int from, to, dist;
13     Edge(){}
14     Edge(int u, int v, int d) :from(u), to(v), dist(d) {}
15 };
16 
17 bool cmp(const Edge &e1,const Edge &e2) {return e1.dist<e2.dist;}
18 
19 Edge wEdgs[maxn*maxn];
20 
21 int main()
22 {
23     int n,m,fr,t,d,adj,ans;
24     while(~scanf("%d",&n)&&n)
25     {
26         int cnt=n-1, unum=0;
27         m=n*(n-1)/2; ans=0;
28         for(int i=1;i<=n;i++) f[i]=i;
29         for(int i=0;i<m;i++)
30         {
31             scanf("%d%d%d%d",&fr,&t,&d,&adj);
32             int q=sf(fr); int w=sf(t);
33             if(adj&q!=w){ f[sf(fr)]=sf(t); cnt--;}
34             else if(!adj) {wEdgs[unum++]=Edge(fr,t,d);}
35         }
36         sort(wEdgs,wEdgs+unum,cmp);
37         for(int i=0;i<unum&&cnt;i++)
38         {
39             int from=wEdgs[i].from; int to=wEdgs[i].to;
40             int q=sf(from); int w=sf(to);
41             if(q!=w){f[q]=w; ans+=wEdgs[i].dist; cnt--;}
42         }
43         printf("%d\n",ans);
44     }
45 }