1 #include<cstdio>
 2 #include<cstring>
 3 #include<stdlib.h>
 4 #include<algorithm>
 5 using namespace std;
 6 const int MAXN=20000+10;
 7 struct node
 8 {
 9     int star;
10     int en;
11     int val;
12     bool operator <(const node &B)const
13     {
14         return val<B.val;
15     }
16 }a[MAXN];
17 int p[MAXN];
18 int Find(int x)
19 {
20     return p[x]==x?x:p[x]=Find(p[x]);
21 }
22 
23 int main()
24 {
25     //freopen("in.txt","r",stdin);
26     int n;
27     while(scanf("%d",&n)&&n)
28     {
29         int temp,val;
30         int num=n*(n-1)/2;
31         for(int i=1;i<=num;i++)
32         {
33             scanf("%d %d %d %d",&a[i].star,&a[i].en,&val,&temp);
34             if(temp==1)
35                 a[i].val=0;
36             else
37                 a[i].val=val;
38         }
39         sort(a+1,a+num+1);
40         for(int i=1;i<=num;i++)
41             p[i]=i;
42         int ans=0,cnt=0;
43         for(int i=1;i<=num;i++)
44         {
45             int x=Find(a[i].star);
46             int y=Find(a[i].en);
47             if(x!=y)
48             {
49                 p[x]=y;
50                 ans+=a[i].val;
51                 cnt++;
52             }
53         }
54             printf("%d\n",ans);
55     }
56     return 0;
57 }