#include <bits/stdc++.h>
using namespace std;
#define sws ios_base::sync_with_stdio(false);cout.tie(NULL);cin.tie(NULL);
#define mp make_pair
#define pb push_back
#define rep(i, a, b) for (int i = a; i < b; i++)
#define dbg(msg,x) cout<<msg<<" "<<x<<endl;
#define output(x) for(auto c:x){cout<<c<<" ";}cout<<" ";
#define int long long
#define ff first
#define ss second
#define endl "\n"
#define pq priority_queue
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<bool> vb;
typedef pair<int, int> pii;
typedef vector<pair<int,int> > vpp;
const int MAXN = 2*1e5+1;
int up[MAXN][19];
int psum[MAXN];
int tin[MAXN];
int tout[MAXN];
int idx=0;
int ans=0;
int cur=0;
struct Edge{
int dest;
int c1;
int c2;
Edge(int a,int b,int c){
dest=a;
c1=b;
c2=c;
}
Edge(){
dest=c1=c2=0;
}
};
vector<Edge> adj[MAXN];
void dfs(int v=1,int p=-1){
up[v][0]=p;
if(p==-1)up[v][0]=v;
rep(i,1,19)up[v][i]=up[up[v][i-1]][i-1];
tin[v]=idx++;
for(auto c:adj[v]){
if(c.dest == p)continue;
dfs(c.dest,v);
}
tout[v]=idx++;
}
int getAns(int v=1,int p=-1){
for(auto c:adj[v]){
if(c.dest == p)continue;
int aux = getAns(c.dest,v);
ans+=min(aux*c.c1,c.c2);
psum[v]+=aux;
}
return psum[v];
}
bool isAncestor(int a,int b){
return tin[a]<=tin[b] && tout[a]>=tout[b];
}
int lca(int a,int b){
if(isAncestor(a,b))return a;
if(isAncestor(b,a))return b;
rep(j,0,19){
int i = 18-j;
if(!isAncestor(up[a][i],b))a=up[a][i];
}
return up[a][0];
}
int32_t main(){
sws
int n;cin>>n;
rep(i,0,n-1){
int a,b,c1,c2;
cin>>a>>b>>c1>>c2;
adj[a].pb(Edge(b,c1,c2));
adj[b].pb(Edge(a,c1,c2));
}
dfs();
rep(i,1,n){
psum[i]++;
psum[i+1]++;
psum[lca(i,i+1)]-=2;
}
getAns();
cout<<ans;
}
