#include <bits/stdc++.h>
#include <time.h>
//#include <random>
//#ifndef _LOCAL
//#pragma GCC optimize("-O3")
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")
//#endif
#define sz(x) int(x.size())
#define in(x) freopen(x, "r", stdin)
#define out(x) freopen(x, "w", stdout)
#define N 2 * 100500
#define oo ll(1e16)
#define pii pair <int, int>
#define pll pair <ll, ll>
#define ft first
#define sd second
#define pb push_back
#define ppb pop_back
#define el '\n'
#define elf endl
#define base ll(1e9 + 7)
#define re return
#define nins 4294967295
using namespace std;
typedef long long ll;
typedef long double ld;
const int LOG = 20;
//mt19937 rnd(0);
struct st {
int v;
ll c1, c2;
st (int v, ll c1, ll c2) : v(v), c1(c1), c2(c2) {}
};
ll n, tin[N], tout[N], timer, up[N][30], f[N];
ll rs, val[N];
vector <st> g[N];
void dfs(int v, int pr = 0) {
tin[v] = timer++;
up[v][0] = pr;
for (int i = 1; i <= LOG; i++)
up[v][i] = up[up[v][i - 1]][i - 1];
for (int i = 0; i < sz(g[v]); i++) {
int nxt = g[v][i].v;
if (nxt == pr)
continue;
dfs(nxt, v);
}
tout[v] = timer++;
}
bool is_anc(int v, int u) {
return (tin[v] < tin[u]) && (tout[v] > tout[u]);
}
int lca(int v, int u) {
if (is_anc(v, u))
return v;
if (is_anc(u, v))
return u;
for (int i = LOG; i >= 0; i--)
if (!is_anc(up[v][i], u))
v = up[v][i];
return up[v][0];
}
void find_res(int v, int pr = 0) {
val[v] = f[v];
for (int i = 0; i < sz(g[v]); i++) {
int nxt = g[v][i].v;
if (nxt == pr)
continue;
find_res(nxt, v);
rs += min(val[nxt] * g[v][i].c1, g[v][i].c2);
val[v] += val[nxt];
}
}
void solve() {
cin >> n;
for (int i = 0; i < n - 1; i++) {
int u, v;
ll c1, c2;
cin >> v >> u >> c1 >> c2; v--; u--;
g[v].pb(st(u, c1, c2));
g[u].pb(st(v, c1, c2));
}
dfs(0);
for (int i = 0; i < n - 1; i++)
f[i]++, f[i + 1]++, f[lca(i, i + 1)] -= 2;
find_res(0);
cout << rs;
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#ifdef _LOCAL
in("input.txt");
int t = 1;
// cin >> t;
for (int i = 1; i <= t; i++) {
cout << "Test #" << i << elf;
clock_t start_time = clock();
solve();
cerr.precision(4); cerr << fixed;
cerr << elf;
cerr << "Time :: " << ld(clock() - start_time) / CLOCKS_PER_SEC << elf;
cout << elf;
}
#else
int t = 1;
// cin >> t;
while (t--) {
solve();
cout << el;
}
#endif
}
