#include <bits/stdc++.h>
using namespace std;
static const long long INF = (1LL << 60);
struct Edge {
int to;
long long w;
};
int N;
vector<vector<Edge>> tree;
vector<long long> leafDist; // distances from root to leaves
vector<long long> vals; // candidate T values
unordered_map<long long, int> id; // value -> index
vector<vector<long long>> dp;
/* Step 1: compute root->leaf distances */
void dfs_dist(int u, int parent, long long dist) {
bool isLeaf = true;
for (auto &e : tree[u]) {
if (e.to == parent) continue;
isLeaf = false;
dfs_dist(e.to, u, dist + e.w);
}
if (isLeaf) leafDist.push_back(dist);
}
/* Step 2: tree DP */
void dfs_dp(int u, int parent) {
bool isLeaf = true;
for (auto &e : tree[u]) {
if (e.to == parent) continue;
isLeaf = false;
dfs_dp(e.to, u);
}
int M = vals.size();
dp[u].assign(M, 0);
if (isLeaf) {
// base case
for (int i = 0; i < M; i++) {
dp[u][i] = llabs(vals[i]);
}
return;
}
// internal node
for (int i = 0; i < M; i++) {
long long T = vals[i];
long long cost = 0;
for (auto &e : tree[u]) {
if (e.to == parent) continue;
long long best = INF;
for (int j = 0; j < M; j++) {
long long x = vals[j];
long long need = T - x;
if (!id.count(need)) continue;
int idx = id[need];
best = min(best,
dp[e.to][idx] + llabs(x - e.w));
}
cost += best;
}
dp[u][i] = cost;
}
}
int main() {
ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> N;
tree.resize(N + 1);
for (int i = 1; i < N; i++) {
int u, v;
long long w;
cin >> u >> v >> w;
tree[u].push_back({v, w});
tree[v].push_back({u, w});
}
// collect leaf distances
dfs_dist(1, 0, 0);
// unique candidate T values
sort(leafDist.begin(), leafDist.end());
leafDist.erase(unique(leafDist.begin(), leafDist.end()), leafDist.end());
vals = leafDist;
for (int i = 0; i < (int)vals.size(); i++)
id[vals[i]] = i;
dp.resize(N + 1);
dfs_dp(1, 0);
long long ans = INF;
for (long long x : dp[1]) ans = min(ans, x);
cout << ans << "\n";
return 0;
}
