#include <bits/stdc++.h>
using namespace std;
#define int long long 
const int N = 1e5+10;
const int mod = 100003;
int n,m;
int qmi(int a,int k){
    int res = 1;
    while(k){
        if(k&1) res = res * a % mod;
        a = a * a % mod;
        k >>= 1;
    }
    return res;
}
vector<pair<int,int>> q[N];
int dp[N];
void solve(){
    cin >> n;
    int m = n - 1;
    while(m--){
        int a,b,c;
        cin >> a >> b >> c;
        q[a].push_back({b,c});
        q[b].push_back({a,c});
    }
    int res = 0;
    auto dfs  = [&](auto&& dfs,int u,int pa) -> void{
        dp[u] = 0;
        for(auto [x,y]:q[u]){
            if(x == pa) continue;
            dfs(dfs,x,u);
            res = max({res,dp[u] + dp[x] + y});
            dp[u] = max({dp[u],dp[x]+y});
        }
    };
    dfs(dfs,1,0);
//  int res = dp[1];
//  cout << dp[1] << '\n';
    // 10 + 11 + 12 
    cout << (11 + 11 + res - 1) * res / 2 << '\n';
}
signed main(){
    int _ = 1;
    // cin >> _;
    while(_--){
        solve();
    }
    return 0;
}