1 #include <cstdio>
 2 #include <cstring>
 3 #include <iostream>
 4 using namespace std;
 5 
 6 const int INF = 0x3f3f3f3f;
 7 int map[110][110], vis[110], dis[110];
 8 int i, j, n;
 9 
10 void Prime()
11 {
12     int sum = 0;
13     memset(vis, 0, sizeof(vis));
14     for(i=1; i<=n; i++)
15         dis[i]=map[1][i];
16     vis[1]=1;
17     for(i=1; i<n; i++)
18     {
19         int temp, min=INF;
20         for(j=1; j<=n; j++)
21         {
22             if(!vis[j] && dis[j] < min)
23             {
24                 min = dis[j];
25                 temp = j;
26             }
27         }
28         vis[temp]=1;
29         sum += min;
30         for(j=1; j<=n; j++)
31             if(!vis[j] && dis[j] > map[temp][j])
32                 dis[j]=map[temp][j];
33     }
34     printf("%d\n", sum);
35 }
36 int main()
37 {
38     while(~scanf("%d", &n), n)
39     {
40         for(i=1; i<=n; i++)
41             for(j=1; j<=n; j++)
42                 map[i][j]=(i==j?0:INF);
43         int u, v, w, p, t; t = n*(n-1)/2;
44         for(i=1; i<=t; i++){
45             scanf("%d %d %d %d", &u, &v, &w, &p);
46             if(p==1)
47                 map[u][v]=map[v][u]=0;
48             else //if(map[u][v] > w)
49                 map[u][v]=map[v][u]=w;
50         }
51         Prime();
52     }
53     return 0;
54 }