//
// Created by Henry Cafaro
// Copyright © 2020 Henry Cafaro. All rights reserved.
//
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <sstream>
#include <queue>
#include <deque>
#include <bitset>
#include <iterator>
#include <list>
#include <stack>
#include <map>
#include <set>
#include <functional>
#include <numeric>
#include <utility>
#include <limits>
#include <time.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
using namespace std;
// === Debug macro starts here ===
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x) {++recur_depth; auto x_=x; --recur_depth; cerr<<string(recur_depth, '\t')<<"\e[91m"<<__func__<<":"<<__LINE__<<"\t"<<#x<<" = "<<x_<<"\e[39m"<<endl;}
#else
#define dbg(x)
#endif
template<typename Ostream, typename ...Ts>
Ostream& operator<<(Ostream& os, const pair<Ts...>& p){
return os<<"{"<<p.first<<", "<<p.second<<"}";
}
template<typename Ostream, typename Cont>
typename enable_if<is_same<Ostream,ostream>::value, Ostream&>::type operator<<(Ostream& os, const Cont& v){
os<<"[";
for(auto& x:v){os<<x<<", ";}
return os<<"]";
}
// === Debug macro ends here ===
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
struct FT {
vector<ll> s;
FT(int n) : s(n) {}
void update(int pos, ll dif) { // a[pos] += dif
for (; pos < sz(s); pos |= pos + 1) s[pos] += dif;
}
ll query(int pos) { // sum of values in [0, pos)
ll res = 0;
for (; pos > 0; pos &= pos - 1) res += s[pos-1];
return res;
}
int lower_bound(ll sum) {// min pos st sum of [0, pos] >= sum
// Returns n if no sum is >= sum, or -1 if empty sum is.
if (sum <= 0) return -1;
int pos = 0;
for (int pw = 1 << 25; pw; pw >>= 1) {
if (pos + pw <= sz(s) && s[pos + pw-1] < sum)
pos += pw, sum -= s[pos-1];
}
return pos;
}
};
vector<vi> treeJump(vi& P){
int on = 1, d = 1;
while(on < sz(P)) on *= 2, d++;
vector<vi> jmp(d, P);
rep(i,1,d) rep(j,0,sz(P))
jmp[i][j] = jmp[i-1][jmp[i-1][j]];
return jmp;
}
int jmp(vector<vi>& tbl, int nod, int steps){
rep(i,0,sz(tbl))
if(steps&(1<<i)) nod = tbl[i][nod];
return nod;
}
int lca(vector<vi>& tbl, vi& depth, int a, int b) {
if (depth[a] < depth[b]) swap(a, b);
a = jmp(tbl, a, depth[a] - depth[b]);
if (a == b) return a;
for (int i = sz(tbl); i--;) {
int c = tbl[i][a], d = tbl[i][b];
if (c != d) a = c, b = d;
}
return tbl[0][a];
}
int n;
struct edge {
int nxt;
ll c1;
ll c2;
};
vector<vector<edge>> adj;
vector<int> p;
vector<int> ht;
vector<int> tin;
vector<int> tout;
vector<ll> cs1;
vector<ll> cs2;
int gt = 0;
void dfs(int x, int par, int h){
dbg(x);
ht[x] = h;
tin[x] = gt++;
for(auto [nxt, c1, c2] : adj[x]){
if(nxt == par)
continue;
p[nxt] = x;
cs1[nxt] = c1;
cs2[nxt] = c2;
dfs(nxt, x, h+1);
}
tout[x] = gt++;
}
void solve(){
cin >> n;
adj.resize(n);
cs1.resize(n);
cs2.resize(n);
p.resize(n);
ht.resize(n);
dbg(ht);
dbg(n);
tin.resize(n);
tout.resize(n);
for(int i = 0; i < n-1; i++){
int a,b;
ll c1,c2;
cin >> a >> b >> c1 >> c2;
a--;b--;
adj[a].push_back({b,c1,c2});
adj[b].push_back({a,c1,c2});
}
dfs(0, -1, 0);
dbg(ht);
dbg(p);
dbg(tin);
dbg(tout);
dbg(cs1);
dbg(cs2);
auto jt = treeJump(p);
auto ft = FT(2*n+2);
for(int i = 0; i+1 < n; i++){
int l = lca(jt, ht, i, i+1);
dbg(l);
ft.update(tin[i], 1);
ft.update(tin[i+1], 1);
ft.update(tin[l], -2);
}
ll ans = 0;
for(int i = 0; i < n; i++){
dbg(i);
dbg(ft.query(tout[i]+1) - ft.query(tin[i]));
ll times = ft.query(tout[i]+1) - ft.query(tin[i]);
ans += min(times * cs1[i], cs2[i]);
}
cout << ans << endl;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
solve();
}
