//1255
#include <bits/stdc++.h>
using namespace std;

const int N = 110, M = 2 * N, INF = 1e9;

int n;
int cnt[N];                            
int h[N], e[M], ne[M], idx;             

void add(int a, int b){
    e[idx] = b, ne[idx] = h[a], h[a] = idx ++ ;
}

int dfs(int u, int father, int dist){
    int sum = cnt[u] * dist;            
    for (int i = h[u]; ~i; i = ne[i]) {
        int j = e[i];
        if (j == father) continue;     
        sum += dfs(j, u, dist + 1);     
    }
    return sum;
}
int main()
{
    cin >> n;
    memset(h, -1, sizeof h);
    for (int i = 1; i <= n; i ++ ){
        int l, r;
        cin >> cnt[i] >> l >> r;       
        if (l) add(i, l), add(l, i);  
        if (r) add(i, r), add(r, i);
    }
    int res = INF;                     
    for (int i = 1; i <= n; i ++ ) res = min(res, dfs(i, -1, 0));
    cout << res << endl;
    return 0;
}