#include <bits/stdc++.h>
using namespace std;
#define for_(i, s, e) for (int i = s; i < (int) e; i++)
#define for__(i, s, e) for (ll i = s; i < e; i++)
typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> ii;
#define endl '\n'
vi ct;
class SegmentTree {
private:
vi tree; int n;
int bound = 0;
void update(int i, int j, int val, int l, int r, int p) {
if (l > j or r < i) return;
if (l >= i and r <= j) {
tree[p] += val;
return;
}
int mid = (l + r) / 2;
int c1 = 2*p+1, c2 = 2*p+2;
update(i, j, val, l, mid, c1); update(i, j, val, mid+1, r, c2);
}
void ans(int l, int r, int p, int inc) {
if (l == r) {
ct[l] = tree[p]+inc;
return;
}
inc += tree[p];
int mid = (l + r) / 2;
int c1 = 2*p+1, c2 = 2*p+2;
ans(l, mid, c1, inc); ans(mid+1, r, c2, inc);
}
public:
void build(int N) {
n = N;
tree.resize(4*n, 0);
}
void update(int i, int j, int val) {
update(i, j, val, 0, n-1, 0);
}
void ans() {
ans(0, n-1, 0, 0);
}
};
int n, pt = 0;
vector<vector<ii>> adj;
vector<ll> c1, c2;
vi heavy, head, pos, depth, parent, node;
SegmentTree tree;
int dfs(int p) {
int sz = 1, maxChildSz = 0;
for (auto i: adj[p]) if (i.first != parent[p]) {
int v = i.first;
node[i.second] = v;
parent[v] = p;
depth[v] = depth[p]+1;
int s = dfs(v);
sz += s;
if (s > maxChildSz) {
maxChildSz = s;
heavy[p] = v;
}
}
return sz;
}
void decompose(int p, int h) {
head[p] = h; pos[p] = pt++;
if (heavy[p] != -1) decompose(heavy[p], h);
for (auto i: adj[p]) if (i.first != parent[p] and i.first != heavy[p]) decompose(i.first, i.first);
}
void query(int a, int b) {
for (; head[a] != head[b]; b = parent[head[b]]) {
if (depth[head[a]] > depth[head[b]]) swap(a, b);
tree.update(pos[head[b]], pos[b], 1);
}
if (depth[a] > depth[b]) swap(a, b);
tree.update(pos[a]+1, pos[b], 1);
}
int main() {
#ifdef shiven
freopen("test.in", "r", stdin);
#endif
ios_base::sync_with_stdio(false);
cin.tie(0);
cin >> n;
adj.resize(n); ct.resize(n); c1.resize(n-1); c2.resize(n-1); parent.resize(n); heavy.resize(n, -1); head.resize(n); pos.resize(n); depth.resize(n); node.resize(n-1);
tree.build(n);
for_(i, 0, n-1) {
int a, b; cin >> a >> b >> c1[i] >> c2[i];
a -= 1; b -= 1;
adj[a].push_back({b, i});
adj[b].push_back({a, i});
}
dfs(0);
decompose(0, 0);
for_(i, 0, n-1) query(i, i+1);
tree.ans();
ll ans = 0;
for_(i, 0, n-1) {
ll a = c1[i], b = c2[i], c = ct[pos[node[i]]];
ans += min(c*a, b);
}
cout << ans << endl;
return 0;
}
