#include <iostream>
#include <vector>
using namespace std;
using ll = long long;
typedef pair < int, int > PII;
typedef pair < PII, PII > Edge;
const int NMAX = 2e5 + 1, LOGMAX = 20;
const int ROOT = 1;
int N;
vector < int > G[NMAX];
vector < Edge > Edges;
int Euler[(NMAX << 1)], First[NMAX];
int Level[NMAX], father[NMAX];
int Log2[(NMAX << 1)];
int rmq[LOGMAX][(NMAX << 1)];
ll ans;
static inline int my_min (int a, int b)
{
return ((a < b) ? a : b);
}
static inline int my_max (int a, int b)
{
return ((a > b) ? a : b);
}
static inline void Read ()
{
ios_base :: sync_with_stdio(false);
cin.tie(nullptr);
cin >> N;
for(int i = 1; i < N; ++i)
{
int a = 0, b = 0, c1 = 0, c2 = 0;
cin >> a >> b >> c1 >> c2;
G[a].push_back(b), G[b].push_back(a);
Edges.push_back({{a, b}, {c1, c2}});
}
return;
}
static inline void DFS (int Node, int from = 0, int lvl = 0)
{
Euler[++Euler[0]] = Node, First[Node] = Euler[0];
Level[Node] = lvl, father[Node] = from;
for(auto it : G[Node])
if(it != from)
{
DFS(it, Node, lvl + 1);
Euler[++Euler[0]] = Node;
}
return;
}
static inline void Build_RMQ ()
{
Log2[1] = 0;
for(int i = 2; i <= Euler[0]; ++i)
Log2[i] = 1 + Log2[(i >> 1)];
for(int i = 1; i <= Euler[0]; ++i)
rmq[0][i] = Euler[i];
for(int i = 1; i <= Log2[Euler[0]]; ++i)
for(int j = 1; j <= Euler[0] - (1 << i) + 1; ++j)
if(Level[rmq[i - 1][j]] < Level[rmq[i - 1][j + (1 << (i - 1))]])
rmq[i][j] = rmq[i - 1][j];
else
rmq[i][j] = rmq[i - 1][j + (1 << (i - 1))];
return;
}
static inline int Query (int left, int right)
{
int lg = right - left + 1;
lg = Log2[lg];
if(Level[rmq[lg][left]] < Level[rmq[lg][right - (1 << lg) + 1]])
return rmq[lg][left];
return rmq[lg][right - (1 << lg) + 1];
}
static inline int LCA (int x, int y)
{
if(x == y)
return x;
return Query(my_min(First[x], First[y]), my_max(First[x], First[y]));
}
static inline void Precalculation ()
{
DFS(ROOT);
Build_RMQ();
return;
}
static inline void my_swap (int &x, int &y)
{
x = (x ^ y), y = (x ^ y), x = (x ^ y);
return;
}
int Mars[(NMAX << 1)];
static inline void Find_Solution ()
{
for(auto it : Edges)
{
int x = it.first.first, y = it.first.second;
int c1 = it.second.first, c2 = it.second.second;
if(Level[x] > Level[y])
my_swap(x, y);
int cnts = Mars[y];
if(1LL * cnts * c1 < 1LL * c2)
ans += 1LL * cnts * c1;
else
ans += 1LL * c2;
}
cout << ans << '\n';
return;
}
int main()
{
Read();
Precalculation();
for(int i = 1; i < N; ++i)
{
int lca = LCA(i, i + 1);
int x = i;
while(x != lca)
++Mars[x], x = father[x];
int y = i + 1;
while(y != lca)
++Mars[y], y = father[y];
}
Find_Solution();
return 0;
}
