1 #include <iostream>
 2 #include <cstdio>
 3 #include <algorithm>
 4 using namespace std;
 5 struct node
 6 {
 7     int s,d,f,g;
 8 } p[5000];
 9 
10 int father[110],sum,k;
11 
12 void set(int n)
13 {
14     for (int i=1; i<=n; i++)
15         father[i]=i;
16 }
17 
18 bool cmp(const node &a,const node &b)
19 {
20     return a.f<b.f;
21 }
22 
23 int find(int a)
24 {
25     if (father[a]==a)return a;
26     return father[a]=find(father[a]);
27 }
28 
29 void Union(int x,int y,int z)
30 {
31     x=find(x);
32     y=find(y);
33     if (x!=y)
34     {
35         sum+=z;
36         father[x]=y;
37         k++;
38     }
39 }
40 
41 int main ()
42 {
43     int n;
44     while (scanf("%d",&n),n)
45     {
46         sum=0;k=0;
47         set(n);
48         for (int i=1; i<=n*(n-1)/2 ; i++)
49         {
50             scanf("%d%d%d%d",&p[i].s,&p[i].d,&p[i].f,&p[i].g);
51             if(p[i].g==1)
52             p[i].f=0;
53         }
54         sort(p+1,p+n*(n-1)/2+1,cmp);
55         for (int i=1; i<=n*(n-1)/2; i++)
56         {
57             Union(p[i].s,p[i].d,p[i].f);
58             if(k==n)
59             break;
60         }
61         printf ("%d\n",sum);
62     }
63     return 0;
64 }