#include <bits/stdc++.h>
#define el '\n'
#define FNAME "PUTOVANJE"
#define allof(x) x.begin(),x.end()
#define allof1(x) x.begin()+1,x.end()
#define mset(x,n) memset(x,(n),sizeof(x))
using namespace std;
const long long MOD = (long long) 1e9 + 7;
template<class X,class Y> bool minimize(X &a,Y b){ if (a>b) {a=b; return true;} return false;}
template<class X,class Y> bool maximize(X &a,Y b){ if (a<b) {a=b; return true;} return false;}
void setup(){
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
if (fopen(FNAME".inp","r")){
freopen(FNAME".inp","r",stdin);
freopen(FNAME".out","w",stdout);
}
}
const int MAXN = 2e5 + 5;
const int LOG = 19;
struct Edges{
int v;
long long one,many;
Edges(int V,long long O,long long ma):v(V),one(O),many(ma){}
};
int n;
vector<Edges> graph[MAXN];
vector<vector<int>> up;
void init(){
cin>>n;
up.assign(LOG+1,vector<int>(n+1,-1));
for (int i=1;i<n;i++){
int u,v,one,many;
cin>>u>>v>>one>>many;
graph[u].emplace_back(v,one,many);
graph[v].emplace_back(u,one,many);
}
}
namespace LCK{
int timedfs;
int in[MAXN],out[MAXN];
void dfs(int u=1,int pre=-1){
up[0][u] = pre;
in[u] = ++timedfs;
for (int k=1;k<=LOG;k++){
if (~up[k-1][u]) up[k][u] = up[k-1][up[k-1][u]];
else up[k][u] = -1;
}
for (const Edges &x : graph[u]){
if (x.v ^ pre){
dfs(x.v,u);
}
}
out[u] = ++timedfs;
}
bool isAncestor(int u,int v){
return (in[u] <= in[v] and out[u] >= out[v]);
}
int LCA(int u,int v){
if (isAncestor(u,v)) return u;
if (isAncestor(v,u)) return v;
for (int k=LOG;k>=0;k--){
if (~up[k][u] and !isAncestor(up[k][u],v)){
u = up[k][u];
}
}
return up[0][u];
}
};
vector<long long> edgeUsed;
long long res = 0;
void dfs(int u=1,int pre=-1){
for (const Edges &x : graph[u]){
int v = x.v;
long long many = x.many;
long long once = x.one;
if (v == pre) continue;
dfs(v,u);
res += min(edgeUsed[v] * once,many);
edgeUsed[u] += edgeUsed[v];
}
}
void sol(){
LCK::dfs();
edgeUsed.assign(n+1,0);
for (int u=1;u<n;u++){
edgeUsed[u]++;
edgeUsed[u+1]++;
edgeUsed[LCK::LCA(u,u+1)]-=2;
}
dfs();
cout<<res;
}
int main(){
setup();
init();
sol();
}
