#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define debug(x) cerr << '[' << (#x) << "] = " << x << '\n';
template<class T> using ordered_set = tree<T, null_type , less<T> , rb_tree_tag , tree_order_statistics_node_update> ;
const int maxn = 2e5 + 5;
struct Edge{
long long to;
long long single, multi;
};
vector<Edge>g[maxn];
long long ans = 0, sub[maxn];
int tin[maxn], tout[maxn], timer, l;
vector<vector<int>>up(maxn, vector<int>(20));
void dfs(int node, int parent, Edge to_parent) {
for(Edge e : g[node]) {
if(e.to!=parent) {
dfs(e.to, node, e);
sub[node] += sub[e.to];
}
}
if(parent!=0) ans += min(sub[node]*to_parent.single, to_parent.multi);
}
void dfs2(int node, int parent) {
tin[node] = timer++;
up[node][0] = parent;
for(int i=1; i<=l; ++i) {
up[node][i] = up[up[node][i-1]][i-1];
}
for(Edge e : g[node]) {
if(e.to!=parent) dfs2(e.to, node);
}
tout[node] = timer++;
}
void PlayGround() {
int n; cin >> n;
l = log2(n) + 2;
for(int i=1; i<n; ++i) {
long long u, v, c, cc; cin >> u >> v >> c >> cc;
Edge e = {v, c, cc};
g[u].emplace_back(e);
e.to = u;
g[v].emplace_back(e);
}
dfs2(1, 1);
auto is_ancestor = [=] (int u, int v) {
return tin[u] <= tin[v] && tout[u] >= tout[v];
};
auto getLCA = [=] (int u, int v) {
if(is_ancestor(u, v))
return u;
if(is_ancestor(v, u))
return v;
for(int i=l; i>=0; --i) {
if(!is_ancestor(up[u][i], v))
u = up[u][i];
}
return up[u][0];
};
for(int i=1; i<n; ++i) {
int lca = getLCA(i, i+1);
if(lca==i) {
sub[i]--;
sub[i+1]++;
} else if(lca==i+1) {
sub[i+1]--;
sub[i]++;
} else {
sub[i]++, sub[i+1]++, sub[lca]-=2;
}
}
Edge e = {0, 0, 0};
dfs(1, 0, e);
cout << ans << '\n';
#ifndef ONLINE_JUDGE
cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
#endif
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
// #ifndef ONLINE_JUDGE
// freopen("input.txt", "r", stdin);
// #endif
PlayGround();
return 0;
}
