#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 5, K = 20;
long long n, a, b, c1, c2, ans, cnt[N], binlift[N][K], depth[N];
struct Edge{
long long b, c1, c2;
};
vector<Edge> tree[N];
void dfs(int v, int p){
binlift[v][0] = p;
for(int i = 1; i < K; i++) binlift[v][i] = binlift[binlift[v][i - 1]][i - 1];
depth[v] = depth[p] + 1;
for(auto e : tree[v]){
if(e.b != p){
dfs(e.b, v);
}
}
}
int lca(int a, int b){
if(depth[b] > depth[a]) swap(a, b);
for(int i = K - 1; i >= 0; i--) if(depth[binlift[a][i]] >= depth[b]) a = binlift[a][i];
if(a == b) return a;
for(int i = K - 1; i >= 0; i--){
if(binlift[a][i] != binlift[b][i]){
a = binlift[a][i], b = binlift[b][i];
}
}
return binlift[a][0];
}
void dfs2(int v, int p){
for(auto e : tree[v]){
if(e.b != p){
dfs2(e.b, v);
ans += min(e.c1 * cnt[e.b], e.c2);
cnt[v] += cnt[e.b];
}
}
}
int main(){
ios_base::sync_with_stdio(false);cin.tie(NULL);
cin >> n;
for(int i = 1; i <= n - 1; i++){
cin >> a >> b >> c1 >> c2;
tree[a].push_back({b, c1, c2});
tree[b].push_back({a, c1, c2});
}
dfs(1, 0);
cnt[1]--, cnt[2]++;
for(int i = 2; i <= n - 1; i++){
int c = lca(i, i + 1);
cnt[c] -= 2;
cnt[i]++, cnt[i + 1]++;
}
dfs2(1, 0);
cout << ans;
}
