/*
$$$$$$$\ $$\ $$$$$$$\
$$ __$$\ \__| $$ __$$\
$$ | $$ | $$$$$$\ $$$$$$\ $$\ $$$$$$$\ $$ | $$ | $$$$$$\ $$$$$$\ $$$$$$$\ $$$$$$\
$$$$$$$\ |$$ __$$\ $$ __$$\ $$ |$$ _____|$$$$$$$\ | \____$$\ $$ __$$\ $$ _____|\____$$\
$$ __$$\ $$ / $$ |$$ | \__|$$ |\$$$$$$\ $$ __$$\ $$$$$$$ |$$ | \__|$$ / $$$$$$$ |
$$ | $$ |$$ | $$ |$$ | $$ | \____$$\ $$ | $$ |$$ __$$ |$$ | $$ | $$ __$$ |
$$$$$$$ |\$$$$$$ |$$ | $$ |$$$$$$$ |$$$$$$$ |\$$$$$$$ |$$ | \$$$$$$$\\$$$$$$$ |
\_______/ \______/ \__| \__|\_______/ \_______/ \_______|\__| \_______|\_______|
*/
#include <bits/stdc++.h>
using namespace std;
#define PB push_back
#define MP make_pair
#define INS insert
#define LB lower_bound
#define UB upper_bound
#define pii pair <int,int>
#define pll pair <long long, long long>
#define si pair<string, int>
#define is pair<int, string>
#define X first
#define Y second
#define _ << " " <<
#define sz(x) (int)x.size()
#define all(a) (a).begin(),(a).end()
#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define FORD(i, a, b) for (int i = (a); i > (b); --i)
#define FORR(i, l, r) for (int i = (l); i <= (r); ++i)
#define FORP(i, a, b) for ((i) = (a); (i) < (b); ++i)
#define FORA(i, x) for (auto &i : x)
#define REP(i, n) FOR(i, 0, n)
#define BITS(x) __builtin_popcount(x)
#define SQ(a) (a) * (a)
#define TRACE(x) cout << #x " = " << (x) << '\n';
#define YES cout << "YES\n"
#define NO cout << "NO\n"
typedef long long ll;
typedef long double ld;
typedef vector <int> vi;
typedef vector <pii> vpi;
typedef vector <ll> vll;
typedef vector <pll> vpl;
typedef vector <double> vd;
typedef vector <ld> vld;
typedef vector<si> vsi;
typedef vector<is> vis;
typedef vector<string> vs;
//((float) t)/CLOCKS_PER_SEC
const int MOD = 1e9 + 7;
const double PI = acos(-1);
const int INF = 1e9 + 10;
const ll INFL = 1e18 + 10;
const int ABC = 30;
const int dx[] = {-1, 1, 0, 0};
const int dy[] = {0, 0, -1, 1};
const int dox[] = {-1, 1, 0, 0, -1, -1, 1, 1};
const int doy[] = {0, 0, -1, 1, -1, 1, -1, 1};
inline int sum(int a, int b){
if (a + b < 0)
return (a + b + MOD) % MOD;
return (a + b) % MOD;
}
inline void add(int &a, int b){
a = sum(a, b);
}
inline int mul(int a, int b){
return (ll)a * (ll)b % MOD;
}
inline int sub(int a, int b){
return (a - b + MOD) % MOD;
}
inline int pot(ll pot, int n){
ll ret = 1;
while (n){
if (n & 1)
ret = (ret * pot) % MOD;
pot = (pot * pot) % MOD;
n >>= 1;
}
return ret;
}
inline int divide(int a, int b){
return mul(a, pot(b, MOD - 2));
}
ll lcm(ll a, ll b){
return abs(a * b) / __gcd(a, b);
}
inline double ccw(pii A, pii B, pii C){
return (A.X * B.Y) - (A.Y * B.X) + (B.X * C.Y) - (B.Y * C.X) + (C.X * A.Y) - (C.Y * A.X);
}
inline int CCW(pii A, pii B, pii C){
double val = ccw(A, B, C);
double eps = max(max(abs(A.X), abs(A.Y)), max(max(abs(B.X), abs(B.Y)), max(abs(C.X), abs(C.Y)))) / 1e9;
if (val <= -eps)
return -1;
if (val >= eps)
return 1;
return 0;
}
void to_upper(string &x){
REP(i, sz(x))
x[i] = toupper(x[i]);
}
void to_lower(string &x){
REP(i, sz(x))
x[i] = tolower(x[i]);
}
string its(ll x){
if (x == 0)
return "0";
string ret = "";
while (x > 0){
ret += (x % 10) + '0';
x /= 10;
}
reverse(all(ret));
return ret;
}
ll sti(string s){
ll ret = 0;
REP(i, sz(s)){
ret *= 10;
ret += (s[i] - '0');
}
return ret;
}
const int N = 2e5 + 10;
const int LOG = 22;
ll n, anc[LOG][N], dep[N], cnt[N];
unordered_map <int, ll> c1[N], c2[N];
vi e[N], razine[N];
void dfs(int node, int dad, int d){
anc[0][node] = dad;
dep[node] = d;
razine[d].PB(node);
FORA(nxt, e[node])
if (nxt != dad)
dfs(nxt, node, d + 1);
}
void dp(){
FOR(i, 1, LOG)
REP(j, n)
anc[i][j] = anc[i - 1][anc[i - 1][j]];
FOR(i,1,LOG)
anc[i][1] =1;
}
void digni(int &node, int k){
REP(i, LOG)
if (k & (1LL << i))
node = anc[i][node];
}
int lca(int x, int y){
if (dep[x] > dep[y])
digni(x, dep[x] - dep[y]);
else if (dep[y] > dep[x])
digni(y, dep[y] - dep[x]);
if (x == y)
return x;
REP(i, LOG){
if (x == y)
break;
x = anc[i][x];
y = anc[i][y];
}
return x;
}
int main () {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
cin >> n;
REP(i, n - 1){
int x, y; cin >> x >> y;
x--, y--;
cin >> c1[x][y] >> c2[x][y];
c1[y][x] = c1[x][y];
c2[y][x] = c2[x][y];
e[x].PB(y);
e[y].PB(x);
}
dfs(0, -1, 0);
dp();
REP(i, n - 1){
int l = lca(i, i + 1);
cnt[i]++;
cnt[i + 1]++;
cnt[l] -= 2;
}
ll sol = 0;
FORD(i, N - 1, -1){
FORA(node, razine[i]){
FORA(nxt, e[node]){
if (dep[nxt] > dep[node]){
sol += min(c2[node][nxt], cnt[nxt] * c1[node][nxt]);
cnt[node] += cnt[nxt];
}
}
}
}
cout << sol << '\n';
return 0;
}
