#include "iostream"

#include "algorithm"

#include "cstdio"

using namespace std;

const int maxn=;

typedef struct

{

    int a,b,v,c;

}node;

int ans;

node graph[maxn*(maxn-)/];

int father[maxn];

int Find(int x)

{

    if(father[x]==x)

        return x;

    else

    {

        father[x]=Find(father[x]);

        return father[x];

    }

}

void Union(int a,int b,int v,int c)

{

    if(Find(a)!=Find(b))

    {

            ans+=v;

            father[Find(a)]=Find(b);

    }

}

bool cmp(node a,node b)

{

    return a.v<b.v;

}

int main()

{

    int N,M;

    while(~scanf("%d",&N)){

        if(N==)

            break;

        M=N*(N-)/;

        ans=;

        for(int i=;i<M;i++)

        {

            scanf("%d%d%d%d",&graph[i].a,&graph[i].b,&graph[i].v,&graph[i].c);

            if(graph[i].c==)

                graph[i].v=;

        }

        for(int i=;i<maxn;i++)

            father[i]=i;

        sort(graph,graph+M,cmp);

        for(int i=;i<M;i++)

            Union(graph[i].a,graph[i].b,graph[i].v,graph[i].c);

        printf("%d\n",ans);

}

    return ;

}