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

int n;
const int N = 110, M = N * 2;
int h[N], e[M], ne[M], idx;
int w[N];
bool st[N];

void add(int a, int b){
    e[idx] = b;
    ne[idx] = h[a];
    h[a] = idx;
    idx++;
}
int dfs(int u , int lev){
    st[u] = 1;
    int sum = w[u] * lev;
    for(int i = h[u]; i != -1;i = ne[i]){
        if(!st[e[i]]) sum += dfs(e[i], lev + 1);
    }
    return sum;
}
int main(){
    memset(h, -1, sizeof h);
    cin >> n;
    for(int i = 1;i <= n; i++){
        int p, l, r;
        cin >> p >> l >> r;
        w[i] = p;
        if(l){
            add(i, l);
            add(l, i);
        }
        if(r){
            add(i, r);
            add(r, i);
        }
    }
    int res = 2e9;
    for(int i = 1;i <= n; ++ i){
        memset(st, 0, sizeof h);
        res = min(res, dfs(i, 0));
    }
    cout << res;
    return 0;
}