//******************/
//* I<3 C++ */
//* I WANT ANY AC */
//* I LOVE PROGRAM!*/
//*IT'S INTERESTING*/
//* I LOVE PROGRAM!*/
//* IN CONTESTS */
//* GET SCORE */
//* AC CODE */
//* LET'S */
//* GO */
//* Written by: */
//* Duc Minh */
#include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <vector>
#include <map>
#include <set>
#include <unordered_set>
#include <stack>
#include <algorithm>
#include <string>
#include <queue>
#include <cctype>
#include <cstring>
#include <iomanip>
#include <deque>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
using namespace std;
// using namespace __gnu_pbds;
#define file(name) freopen(name".inp", "r", stdin);\
freopen(name".out", "w", stdout);
#define ordered_set tree<ll, null_type,less_equal<ll>, rb_tree_tag,tree_order_statistics_node_update>
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
#define all(a) a.begin(),a.end()
#define endl "\n"
#define all1(a) a+1,a+n+1
#define unordered_map map
// #define push_back emplace_back
// #define gcd(a,b) __gcd(a,b);
// #define lcm(a,b) (a*b)/gcd(a,b);
const long long INF = (long long)1e18;
const long long MOD = (long long)1e9+7;
const long long MODD = 2024; /// 998244353
const long long maxN = 1e6+9;
const int LOG = 31;
const int mlift = 19;
template<class A> inline int __lg(A &a) { return static_cast<int>(log2(a));}
template<class A,class B> inline void add(A &a,B b) { a+=b;while (a>=MOD) a-=MOD;}
template<class A,class B> inline void minus(A &a,B b) { a-=b;while (a>=MOD) a-=MOD;while (a<0) a+=MOD;}
///--------------------------------
void solve();
signed main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
// file("BAI4");
long long t;
// cin >> t;
t=1;
while (t--){
solve();
}
cerr << "Time elapsed: " << TIME << "s.\n";
cerr << "ducminh" << "\n";
return 0;
}
///--------------------[PROBLEM SOLUTION]--------------------///
struct minh{
long long v, mm1,mm2, pos;
};
vector<minh> a[200009];
long long luu[200009],n,cost[200009],f[200009],sl[200009],mm1[200009],mm2[200009];
// LCA
long long p[20][200005];
void DFS(long long u){
for (long long i=0; i<a[u].size(); i++){
long long v=a[u][i].v;
if (p[0][u] != v){
p[0][v]=u;
cost[v]=cost[u]+a[u][i].mm1;
luu[v]=luu[u]+1;
for (long long i=1; i<=mlift; i++){
p[i][v]= p[i-1][p[i-1][v]];
}
DFS(v);
}
}
}
long long LCA(long long u, long long v){
if (luu[u]<luu[v]) swap(u,v);
long long diff = luu[u]-luu[v];
for (long long i=0; i<=mlift; i++){
if ((diff>>i) & 1){
u=p[i][u];
}
}
// cout << u << ' ' << v << "\n";
if (u==v) return u;
for (long long i=mlift; i>=0; i--){
if (p[i][u]!=p[i][v]){
u=p[i][u];
v=p[i][v];
}
}
return p[0][u];
}
long long lifting(long long u, long long k){
for (long long i=0; i<=mlift; i++){
if ((k>>i) & 1){
u=p[i][u];
}
}
return u;
}
long long getdist(long long u, long long v){
return cost[u]+cost[v]-cost[LCA(u,v)];
}
long long dp[200009];
void dfs(long long u, long long par, long long pos){
dp[u]=f[u];
for (auto x: a[u]){
if (x.v==par) continue;
dfs(x.v,u,x.pos);
dp[u]+=dp[x.v];
}
if (pos!=-1) sl[pos]=dp[u];
}
void solve(){
cin >> n;
for (long long i=1; i<n; i++){
long long x, y;
cin >> x >> y >> mm1[i] >> mm2[i];
a[x].push_back({y,mm1[i],mm2[i],i});
a[y].push_back({x,mm1[i],mm2[i],i});
}
DFS(1);
// cout << LCA(1,2) << "\n";
// cout << getdist(1,4) << "\n";
for (long long i=1; i<n; i++){
f[i]++;
f[i+1]++;
f[LCA(i,i+1)]-=2;
}
dfs(1,-1,-1);
long long ans=0;
for (long long i=1; i<n; i++){
// cout << i << ' ' << sl[i] << ' ' << f[i] << "\n";
ans+=min(mm1[i]*sl[i],mm2[i]);
}
cout << ans;
}
