#include <bits/stdc++.h>
//#pragma GCC optimize("unroll-loops")
//#pragma GCC optimize("-O3")
//#pragma GCC optimize("Ofast")
#define F first
#define S second
#define sz(x) int(x.size())
#define pb push_back
#define N 200005
#define M ll(1000000007)
using namespace std;
typedef long long ll;
vector <pair <pair <int, ll>, ll> > g[N];
ll ans;
int n, in[N], out[N], tp;
void dfs(int v, int p, set <int> &vr, ll c1, ll c2)
{
for (auto it : g[v])
{
if (it.F.F == p) continue;
set <int> pt; pt.clear();
dfs(it.F.F, v, pt, it.F.S, it.S);
for (auto itr : pt) vr.insert(itr);
}
vr.insert(v);
if (v != 1)
{
ll kol = 0, lst = -1;
for (auto it : vr)
{
if (lst + 1 != it) kol += 2;
lst = it;
if (it == n) kol--;
}
ans += min(c1 * kol, c2);
}
}
void rec(int v, int p)
{
in[v] = tp++;
for (auto it : g[v])
{
if (it.F.F == p) continue;
rec(it.F.F, v);
}
out[v] = tp++;
}
void dfser(int v, int p, vector <int> &vr, ll c1, ll c2)
{
for (auto it : g[v])
{
if (it.F.F == p) continue;
vector <int> gr; gr.clear();
dfser(it.F.F, v, gr, c1, c2);
for (auto itr : gr) if (itr < in[v] || out[v] < itr) vr.pb(itr);
}
if (v != 1)
{
if (v != n && (in[v + 1] < in[v] || out[v] < in[v + 1])) vr.pb(in[v + 1]);
ll kol = 2 + sz(vr) * 2;
if (in[v] <= in[n] && out[n] <= out[v]) kol--;
ans += max(c1 * kol, c2);
}
}
int main()
{
//freopen("mining.in","r",stdin); freopen("mining.out","w",stdout);
ios_base::sync_with_stdio(0); istream::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
for (ll i = 1; i < n; i++)
{
ll x, y, c1, c2;
cin >> x >> y >> c1 >> c2;
g[x].pb({{y, c1}, c2});
g[y].pb({{x, c1}, c2});
}
if (n <= 2000)
{
set <int> st; st.clear();
dfs(1, -1, st, -1, -1);
}
else
{
rec(1, -1);
vector <int> gr; gr.clear();
dfser(1, -1, gr, -1, -1);
}
cout << ans << endl;
}
