#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define ii pair<ll,ll>
#define iii pair<ll,ii>
#define endl '\n'
struct E{
int node;
int c1,c2;
E(int a,int b,int c){
node=a;
c1=b,c2=c;
}
};
int n;
vector<E> al[200005];
int in[200005]; //preorder
int out[200005]; //postorder
int st[200005]; //subtree size
int parent[200005]; //first parent
int hparent[200005]; //parent on heavy path
int depth[200005];
void dfs_st(int i,int p){
parent[i]=p;
st[i]=1;
if (al[i][0].node==p && al[i].size()>1) swap(al[i][0],al[i][1]);
for (auto &it:al[i]){ ///& is important here
if (it.node==p) continue;
depth[it.node]=depth[i]+1;
dfs_st(it.node,i);
st[i]+=st[it.node];
if (st[it.node]>st[al[i][0].node]){
swap(it,al[i][0]);
//we ensure heavy child is al[i][0]
}
}
}
int dfs_time=0;
void dfs_hld(int i,int p){
in[i]=dfs_time++;
for (auto it:al[i]){
if (it.node==p) continue;
hparent[it.node]=(it.node==al[i][0].node)?hparent[i]:it.node;
dfs_hld(it.node,i);
}
out[i]=dfs_time;
}
struct node{
int s,e,m;
long long val=0;
node *l,*r;
node(int _s,int _e){
s=_s,e=_e,m=(s+e)>>1;
if (s!=e){
l=new node(s,m);
r=new node(m+1,e);
}
}
long long query(int i){
if (s==e) return val;
else if (i<=m) return val+l->query(i);
else return val+r->query(i);
}
void update(int i, int j, long long k){
if (s==i && e==j) val+=k;
else if (j<=m) l->update(i,j,k);
else if (m<i) r->update(i,j,k);
else l->update(i,m,k),r->update(m+1,j,k);
}
}*root=new node(0,400005);
void hld_update(int i,int j){
while (hparent[i]!=hparent[j]){
if (depth[hparent[i]]<depth[hparent[j]]) swap(i,j);
root->update(in[hparent[i]],in[i],1);
i=parent[hparent[i]];
}
if (in[i]>in[j]) swap(i,j);
if (i!=j) root->update(in[i]+1,in[j],1);
}
ll C1[200005];
ll C2[200005];
void dfs(int i,int p){
for (auto &it:al[i]){
if (it.node==p) continue;
C1[it.node]=it.c1;
C2[it.node]=it.c2;
dfs(it.node,i);
}
}
int main(){
ios::sync_with_stdio(0);
cin.tie(0);
cin>>n;
int a,b,c,d;
for (int x=1;x<n;x++){
cin>>a>>b>>c>>d;
al[a].push_back(E(b,c,d));
al[b].push_back(E(a,c,d));
}
parent[1]=0;
hparent[1]=1;
dfs_st(1,-1);
dfs_hld(1,-1);
for (int x=1;x<n;x++) hld_update(x,x+1);
dfs(1,-1);
ll ans=0;
//for (int x=1;x<=n;x++) cout<<root->query(in[x])<<" "<<C1[x]<<" "<<C2[x]<<endl;
for (int x=2;x<=n;x++) ans+=min(root->query(in[x])*C1[x],C2[x]);
cout<<ans<<endl;
}
