#include <bits/stdc++.h>
using namespace std;
typedef pair<int, int> ii;
map<int, ii> EdgeW[200005];
vector<int> AdjList[200005];
static int heavy[200005];
static int depth[200005];
static int head[200005];
static int p[200005];
static int pos[200005];
static int sz[200005];
int cnt = 0; ///set to 1 if you're using fenwick tree
long long A[200005];
long long val[(1<<19)+5];
long long lazyadd[(1<<19)+5];
int N;
inline int left1(int x){
return (x<<1)+1;
}
inline int right1(int x){
return (x<<1)+2;
}
long long value(int i, int s, int e){
if(s == e){
val[i] += lazyadd[i];
lazyadd[i] = 0;
return val[i];
}
int l = left1(i);
int r = right1(i);
val[i] += lazyadd[i];
lazyadd[l] += lazyadd[i];
lazyadd[r] += lazyadd[i];
lazyadd[i] = 0;
return val[i];
}
void init(int i = 0, int s = 0, int e = N-1){
int m = (s+e)>>1;
lazyadd[i] = 0;
if(s == e){
val[i] = A[s];
}else{
int l = left1(i);
int r = right1(i);
init(l, s, m);
init(r, m+1, e);
val[i] = val[l]+val[r];
}
}
long long rsq(int x, int y, int i = 0, int s = 0, int e = N-1){
int m = (s+e)>>1;
value(i, s, e);
if(x <= s && e <= y){
return val[i];
}
int l = left1(i);
int r = right1(i);
if(x > m){
return rsq(x, y, r, m+1, e);
}else if(y <= m){
return rsq(x, y, l, s, m);
}else{
return rsq(x, y, r, m+1, e)+rsq(x, y, l, s, m);
}
}
void update(int x, int y, int v, int i = 0, int s = 0, int e = N-1){
int m = (s+e)>>1;
if(x <= s && e <= y){
lazyadd[i] += v;
return;
}
int l = left1(i);
int r = right1(i);
if(x > m){
update(x, y, v, r, m+1, e);
}else if(y <= m){
update(x, y, v, l, s, m);
}else{
update(x, y, v, r, m+1, e);
update(x, y, v, l, s, m);
}
val[i] = value(l, s, m)+value(r, m+1, e);
}
void dfs(int u){
sz[u] = 1;
int maxChild = 0;
for(int v : AdjList[u]){
if(sz[v] == 0){
depth[v] = depth[u] + 1;
dfs(v);
sz[u] += sz[v];
p[v] = u;
if(sz[v] > maxChild){
maxChild = sz[v];
heavy[u] = v;
}
}
}
}
void decompose(int u, int h){
head[u] = h;
pos[u] = cnt;
cnt++;
if(heavy[u] != 0) decompose(heavy[u], h);
for(int v : AdjList[u]){
if(sz[v] < sz[u] && v != heavy[u]){
decompose(v,v);
}
}
}
void update1(int a, int b){
if(depth[a] > depth[b]) swap(a,b);
for(;head[a] != head[b];b = p[head[b]]){
if(depth[head[a]] > depth[head[b]]) swap(a,b);
update(pos[head[b]],pos[b],1);
///any update and query affects pos[head[b]] inclusive to pos[b] inclusive
}
if(depth[a] > depth[b]) swap(a,b);
if(pos[a] == pos[b]){return;}
update(pos[a]+1,pos[b],1);
}
long long sum1(int a, int b){
long long res = 0;
if(depth[a] > depth[b]) swap(a,b);
for(;head[a] != head[b];b = p[head[b]]){
if(depth[head[a]] > depth[head[b]]) swap(a,b);
res += rsq(pos[head[b]],pos[b]);
///any update and query affects pos[head[b]] inclusive to pos[b] inclusive
}
if(depth[a] > depth[b]) swap(a,b);
if(pos[a] == pos[b]){return res;}
res += rsq(pos[a]+1,pos[b]);
return res;
}
int main(){
scanf("%d", &N);
for(int i = 1; i < N; i ++){
int a, b, c, d;
scanf("%d%d%d%d", &a, &b, &c, &d);
AdjList[a].push_back(b);
AdjList[b].push_back(a);
EdgeW[a][b] = ii(c, d);
EdgeW[b][a] = ii(c, d);
}
init();
dfs(1);
decompose(1,1);
for(int i = 1; i < N; i ++){
update1(i, i+1);
}
long long ans = 0;
for(int i = 1; i <= N; i ++){
for(int j: AdjList[i]){
if(j < i){continue;}
int x, y;
tie(x, y) = EdgeW[i][j];
//printf("%d %d\n", i, j);
long long times = sum1(i, j);
//printf("%d %d %lld\n", i, j, times);
ans += min(x*times, (long long)y);
}
}
printf("%lld", ans);
return 0;
}
