#include<iostream>
#include<vector>
#include<map>
#include<set>
#include<cassert>
#include<cassert>
#include<unordered_map>
#include<unordered_set>
#include<functional>
#include<queue>
#include<stack>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<sstream>
#include<iomanip>
#include<cstdio>
#include<cstdlib>
#include<numeric>
#include<random>
#include<chrono>
#include<bitset>
using namespace std;
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define xx first
#define yy second
#define sz(x) (int)(x).size()
#define gc getchar
#define IO ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define mp make_pair
#ifndef ONLINE_JUDGE
# define LOG(x) (cerr << #x << " = " << (x) << endl)
#else
# define LOG(x) ((void)0)
#endif
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
const double PI=3.1415926535897932384626433832795;
const ll INF = 1LL<<62;
const ll MINF = -1LL<<62;
template<typename T> T getint() {
T val=0;
char c;
bool neg=false;
while((c=gc()) && !(c>='0' && c<='9')) {
neg|=c=='-';
}
do {
val=(val*10)+c-'0';
} while((c=gc()) && (c>='0' && c<='9'));
return val*(neg?-1:1);
}
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count()); uniform_int_distribution<int>(0, n-1)(rng)
int n;
vector<pair<int,int>> adj[200001];
set<int> lst[200001];
int st[200001];
ll c[2][200001];
int par[200001], par_e[200001];
ll cnt[200001];
ll solve(int x) {
st[x]=1;
ll cost=0;
for(auto i:adj[x]) {
if(!st[i.xx]) {
par[i.xx]=x;
par_e[i.xx]=i.yy;
cost+=solve(i.xx);
}
}
if(!cost) {
lst[x].insert(x);
return cnt[par_e[x]]=2;
}
ll mx=adj[x][0].xx;
for(auto i:adj[x]) {
if(par[i.xx]==x) {
if(lst[i.xx].size()>lst[mx].size()) mx=i.xx;
}
}
auto berak=[&](int j) {
auto it=lst[x].insert(j).xx;
int elotte=(it!=lst[x].begin()&&*prev(it)==j-1);
int utana=(it!=prev(lst[x].end())&&*next(it)==j+1);
if(!elotte && !utana) {
cost+=2;
}else if(elotte+utana==1) {
}else {
cost-=2;
}
};
lst[x].swap(lst[mx]);
//cerr<<cnt[mx]<<"\n";
cost=cnt[par_e[mx]];
berak(x);
for(auto i:adj[x]) {
if(par[i.xx]==x) {
for(auto j:lst[i.xx]) {
berak(j);
}
}
}
/*cerr<<x<<": ";
for(auto i:lst[x]) cerr<<i<<" ";
cerr<<"\n";*/
return cnt[par_e[x]]=cost;
}
int main() {
IO;
cin>>n;
for(int i=1;i<n;++i) {
int a,b;
cin>>a>>b>>c[0][i]>>c[1][i];
adj[a].push_back({b,i});
adj[b].push_back({a,i});
}
solve(1);
int akt=n;
while(akt!=1) {
cnt[par_e[akt]]--;
akt=par[akt];
}
ll ans=0;
for(int i=1;i<n;++i) {
//cerr<<i<<" "<<cnt[i]<<"\n";
ans+=min(c[0][i]*cnt[i], c[1][i]);
}
cout<<ans<<"\n";
return 0;
}
