hdu_1879

/*
 * 最小生成树，已修建的道路费用为0
*/
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

#define MAXN    101
#define MAXM    10001
#define INF     0x3f3f3f3f

struct Edge {
        int u, v, w;
}edge[MAXM];

int e_cnt, root[MAXN];

void insert_arc(int u, int v, int w)
{
        edge[e_cnt].v = v;      edge[e_cnt].w = w;
        edge[e_cnt ++].u = u;
}

int cmp(const struct Edge &a, const struct Edge &b)
{
        return a.w < b.w;
}

int get_root(int x)
{
        if( x == root[x] ) {
                return x;
        }
        return root[x] = get_root(root[x]);
}

int min_spanning_tree(int vertex)
{
        int rx, ry, ans(0);
        for(int i = 1; i <= vertex; i ++ ) {
                root[i] = i;
        }
        for(int i = 1; i < vertex; i ++) {
                for(int j = 0; j < e_cnt; j ++) {
                        rx = get_root(edge[j].u); ry = get_root(edge[j].v);
                        if( rx != ry ) {
                                root[rx] = ry;
                                ans += edge[j].w;
                                break;
                        }
                }
        }
        return ans;
}

int main(int argc, char const *argv[])
{
#ifndef ONLINE_JUDGE
        freopen("test.in", "r", stdin);
#endif
        int vertex, arc, u, v, w, mark;
        while( scanf("%d", &vertex) && vertex ) {
                arc = (vertex*(vertex-1))/2; e_cnt = 0;
                for(int i = 0; i < arc; i ++) {
                        scanf("%d %d %d %d", &u, &v, &w, &mark);
                        if( !mark ) {
                                insert_arc(u, v, w);
                        }
                        else {
                                insert_arc(u, v, 0);
                        }
                }
                sort(edge, edge+e_cnt, cmp);
                printf("%d\n", min_spanning_tree(vertex));
        }
        return 0;
}