#include <bits/stdc++.h>
using namespace std;
#define MAX_N 200005
vector<pair<int,int> >adjl[200005];
int p[200005];
int h[200005];
int head[200005];
int pos[200005];
long long fenwick[MAX_N];
int cur = 0;
long long o1[200005];
long long o2[200005];
int val[200005];
int heavy[200005];
void update(int po, long long val){
//printf("upd %d with %d\n",po,val);
while (po<MAX_N){
fenwick[po] += val;
po += (po&(-po));
}
}
long long query(int a){
long long ans = 0;
while (a>0){
ans += fenwick[a];
a -= (a&(-a));
}
return ans; //I NEED TO STOP FORGETTING THIS
}
long long query(int a, int b){
return query(b)-query(a-1);
}
int dfs(int node, int parent, int height){
h[node] = height;
p[node] = parent;
int cursize = 1;
int maxsize = -1;
for (auto x : adjl[node]){
if (x.first==parent) {
val[node] = x.second;
continue;
}
int t = dfs(x.first,node,height+1);
if (t>maxsize){
heavy[node] = x.first;
maxsize = t;
}
cursize+=t;
}
return cursize;
}
void decomp(int node, int he){
head[node] = he;
pos[node] = cur;
cur++;
if (heavy[node]!=-1) decomp(heavy[node],he);
for (auto x : adjl[node]){
if (x.first == p[node]) continue;
if (x.first == heavy[node]) continue;
decomp(x.first,x.first);
}
}
int main(){
int n;
scanf("%d",&n);
for (int x = 0; x<n-1; x++){
int a,b,c,d;
scanf("%d%d%d%d",&a,&b,&c,&d);
adjl[a].push_back({b,x});
adjl[b].push_back({a,x});
o1[x] = d;
o2[x] = c;
}
memset(heavy,-1,sizeof(heavy));
dfs(1,-1,0);
decomp(1,1);
for (int x = 2; x<=n; x++){
int a = x-1;
int b = x;
while (head[a]!=head[b]){
if (h[head[a]]<h[head[b]]) {
int t = a;
a = b;
b = t;
}
update(pos[head[a]],1);
update(pos[a]+1,-1);
a = p[head[a]];
}
if (a!=b){
update(min(pos[a],pos[b])+1,1);
update(max(pos[a],pos[b])+1,-1);
}
}
long long ans = 0;
for (int x = 2; x<=n; x++){
long long option1 = o1[val[x]];
long long option2 = o2[val[x]]*query(pos[x]);
ans += min(option1,option2);
}
printf("%lld",ans);
}
