#include <bits/stdc++.h>
using namespace std;
const int mxN = 2e5 + 100;
vector<pair<int, int>> adj[mxN];
pair<int, int> edge[mxN];
int edge_idx[mxN], pre[mxN];
struct BinaryLifting{
vector<int> parent, depth;
vector<vector<int>> dp;
int N, mxB;
void init(int n){
N = n, mxB = __lg(N) + 5;
parent.resize(N + 1), depth.resize(N + 1);
dp.resize(N + 5, vector<int>(mxB, 0));
}
void dfs(int u = 1, int par = 0){
parent[u] = par;
depth[u] = depth[par] + 1;
dp[u][0] = par;
for(int i = 1; i < mxB; ++i) dp[u][i] = dp[dp[u][i - 1]][i - 1];
for(auto [v, i] : adj[u]){
if(v ^ par){
edge_idx[v] = i;
dfs(v, u);
}
}
}
void done(int u = 1, int par = 0){
for(auto it : adj[u]){
if(it.first ^ par){
done(it.first, u);
pre[u] += pre[it.first];
}
}
}
int kth(int u, int k){
for(int i = 0; i < mxB; ++i){
if(k & (1ll << i)) u = dp[u][i];
}
return u;
}
int lca(int u, int v){
if(depth[u] < depth[v]) swap(u,v);
u = kth(u, abs(depth[u] - depth[v]));
if(u == v) return u;
for(int i = mxB - 1; i >= 0; --i){
if(dp[u][i] != dp[v][i]){
u = dp[u][i];
v = dp[v][i];
}
}
return dp[u][0];
}
int dist(int u, int v){
return depth[u] + depth[v] -2 * depth[lca(u,v)];
}
void update(int u, int v){
int lc = lca(u, v);
pre[u] += 1, pre[v] += 1, pre[lc] -= 2;
}
} helper;
signed main(){
ios::sync_with_stdio(0);
cin.tie(nullptr); cout.tie(nullptr);
int n;
cin >> n;
for(int i = 0, u, v, c0, c1; i < n - 1; ++i){
cin >> u >> v >> c0 >> c1;
adj[u].push_back({v, i});
adj[v].push_back({u, i});
edge[i] = {c0, c1};
}
helper.init(n);
helper.dfs();
for(int i = 1; i <= n - 1; ++i){
helper.update(i, i + 1);
}
helper.done();
long long ans = 0;
for(int i = 2; i <= n; ++i){
ans += (long long) min((long long) edge[edge_idx[i]].first * pre[i], (long long) edge[edge_idx[i]].second);
}
cout << ans << "\n";
return 0;
}
