#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define eb emplace_back
#define mt make_tuple
#define all(x) (x).begin(), (x).end()
#define sz(x) int(x.size())
#define MOD 1000000007
typedef long long ll;
typedef pair <int, int> ii;
typedef pair <ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef long double ld;
const ll INF=63;
const int mxn=2e5+5;
bool DEBUG=0;
int n;
vector<ii>adj[mxn];
ll c[mxn][2];
int cnt[mxn],cnt2[mxn],par[18][mxn],dep[mxn];
void dfs(int u, int p){
for(ii x:adj[u]){
int v=x.fi;
if(v==p)continue;
par[0][v]=u;
dep[v]=dep[u]+1;
dfs(v,u);
}
}
int lca(int u, int v){
if(dep[u]<dep[v])swap(u,v);
int dif = dep[u]-dep[v];
for(int i=0; i<18; i++){
if(dif>>i&1)u=par[i][u];
}
if(u==v)return u;
for(int i=17; i>=0; i--){
if(par[i][u]!=par[i][v]){
u=par[i][u];
v=par[i][v];
}
}
return par[0][u];
}
void dfs2(int u, int p){
for(ii x:adj[u]){
int v=x.fi;
int ind=x.se;
if(v==p)continue;
dfs2(v,u);
cnt2[ind]=cnt[v];
cnt[u]+=cnt[v];
}
}
void solve(int u, int v){
int LCA = lca(u,v);
cnt[u]++;
cnt[v]++;
cnt[LCA]-=2;
/*
cerr<<u<<" "<<LCA<<": \n";
for(int i=1; i<=n; i++){
cerr<<i<<" "<<cnt[i]<<"\n";
}
*/
}
int main()
{
ios_base::sync_with_stdio(0); cin.tie(0);
//freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
cin>>n;
for(int i=0; i<n-1; i++){
int u,v;
cin>>u>>v>>c[i][0]>>c[i][1];
adj[u].eb(v,i);
adj[v].eb(u,i);
}
dep[1]=1;
dfs(1,0);
for(int i=1; i<18; i++){
for(int j=1; j<=n; j++){
if(par[i-1][j]){
par[i][j]=par[i-1][par[i-1][j]];
}
}
}
for(int i=1; i<=n-1; i++)solve(i,i+1);
/*
int LCA = lca(n,1);
cnt[n]--; cnt[1]--;
cnt[LCA]+=2;
for(int i=1; i<=n; i++){
cerr<<i<<" "<<cnt[i]<<"\n";
}
*/
dfs2(1,0);
/*
for(int i=1; i<=n; i++){
cerr<<i<<" "<<cnt[i]<<"\n";
}
*/
ll ans=0ll;
for(int i=0; i<n-1; i++){
if(cnt2[i]){
ll p1=1ll*cnt2[i]*c[i][0];
if(p1<=c[i][1]){
ans+=p1;
}else{
ans+=c[i][1];
}
}
}
cout<<ans;
}
// READ & UNDERSTAND
// ll, int overflow, array bounds, memset(0)
// special cases (n=1?), n+1 (1-index)
// do smth instead of nothing & stay organized
// WRITE STUFF DOWN
