#include<bits/stdc++.h>
using namespace std;
const int N = 200100;
const int K = 20;
vector<int> adj[N];
int pai[N][K], in[N], out[N], cs = 0;
long long cost[N];
void pre_dfs(int u, int p)
{
in[u] = cs++;
pai[u][0] = p;
for(int i = 1; i < K; i++)
pai[u][i] = pai[pai[u][i-1]][i-1];
for(int v : adj[u])
if(v != p)
pre_dfs(v, u);
out[u] = cs++;
}
// u is ancestor of v ?
bool is_ancestor(int u, int v)
{
return in[u] <= in[v] && out[v] <= out[u];
}
int calc_lca(int a, int b)
{
if(is_ancestor(a, b))
return a;
if(is_ancestor(b, a))
return b;
for(int i = K-1; i >=0; i--)
{
if(!is_ancestor(pai[b][i], a))
b = pai[b][i];
}
return pai[b][0];
}
map<pair<int,int>,pair<int,int>> mp;
long long rs = 0;
void dfs(int u, int p)
{
for(int v : adj[u])
if(v != p)
{
dfs(v, u);
cost[u] += cost[v];
}
rs += min(mp[{u,p}].first*cost[u],(long long)mp[{u,p}].second);
}
void test()
{
int n;
cin >> n;
for(int i = 0, u, v, c1, c2; i < n-1; i++)
{
cin >> u >> v >> c1 >> c2;
mp[{u,v}] = mp[{v,u}] = {c1,c2};
adj[u].push_back(v);
adj[v].push_back(u);
}
pre_dfs(1, 1);
for(int i = 1; i < n; i++)
{
int lc = calc_lca(i, i+1);
cost[lc] -=2;
cost[i] += 1;
cost[i+1] += 1;
}
dfs(1, 1);
cout << rs << '\n';
}
int32_t main()
{
ios::sync_with_stdio(false);
cin.tie(NULL);
test();
return 0;
}
