#include <bits/stdc++.h>
using namespace std;
const int N = 110;
vector<int> e[N];
int n, w[N], sz[N], f[N], res = 2e9;
void dfs1(int u, int dep){
    sz[u] = w[u], f[1] += w[u] * dep;
    for(int v: e[u]){
        dfs1(v, dep + 1);
        sz[u] += sz[v];
    }
}
void dfs2(int u){
    res = min(res, f[u]);
    for(int v: e[u]){
        f[v] = f[u] + sz[1] - 2 * sz[v];
        dfs2(v);
    }
}
int main(){
    cin >> n;
    for(int i = 1; i <= n; i++){
        int u, v;
        cin >> w[i] >> u >> v;
        if(u) e[i].push_back(u);
        if(v) e[i].push_back(v);
    }
    dfs1(1, 0), dfs2(1);
    cout << res;

    return 0;
}