#include <bits/stdc++.h>
using namespace std;
const int N = 1000010;
const int INF = 0x3f3f3f3f;

int g[150][150];
int w[N];

int main() {
    int n;
    cin >> n;

    // 地图初始化
    memset(g, 0x3f, sizeof g);
    for (int i = 1; i <= n; i++) g[i][i] = 0;

    for (int i = 1; i <= n; i++) {
        int a, b;
        cin >> w[i] >> a >> b;
        if (a) g[i][a] = g[a][i] = 1; // 左链接，右链接，二叉树，和一般的不一样
        if (b) g[i][b] = g[b][i] = 1;
    }

    // floyd
    for (int k = 1; k <= n; k++)
        for (int i = 1; i <= n; i++)
            for (int j = 1; j <= n; j++)
                if (g[i][j] > g[i][k] + g[k][j]) g[i][j] = g[i][k] + g[k][j];

    int ans = INF;
    for (int i = 1; i <= n; i++) {
        int s = 0;
        for (int j = 1; j <= n; j++) s += w[j] * g[i][j];
        ans = min(ans, s);
    }
    printf("%d", ans);
    return 0;
}