#include <iostream>
#include <cstdio>
#include <vector>

using namespace std;

const int N = 1e5 + 10;

struct Edge
{
    int id, w;
};

vector<Edge> h[N];
int dist[N];

void dfs(int u, int father, int distance)
{
    dist[u] = distance;

    for (auto node : h[u])
        if (node.id != father)
            dfs(node.id, u, distance + node.w);
}


int main()
{
    int n;
    scanf("%d", &n);
    for (int i = 1; i <= n - 1; i ++ )
    {
        int p, q, d;
        scanf("%d%d%d", &p, &q, &d);
        h[p].push_back({q, d});
        h[q].push_back({p, d});
    }

    dfs(1, -1, 0);

    int u = 1;
    for (int i = 2; i <= n; i ++ )
        if (dist[u] < dist[i]) u = i;



    dfs(u, -1, 0);

    int distance = 0;
    for (int i = 1; i <= n; i ++ )
        if (distance < dist[i]) distance = dist[i];

    printf("%lld\n", distance * 10 + distance * (distance + 1ll)/2 );  //1ll使整个表达式的值变成long long类型

    return 0;
}