package tiantiDaily;

import java.util.Scanner;

class TreeNode {
    int val;
    int left;
    int right;
    int father;

    TreeNode(int x) {
        val = x;
    }
}

public class _H {

    static int n, sum, ans = Integer.MAX_VALUE;
    static TreeNode[] t = new TreeNode[106];
    static int[] vis = new int[105];

    public static void dfs(int step, int pos) {
        sum += step * t[pos].val;
        int fa = t[pos].father, l = t[pos].left, r = t[pos].right;

        if (fa != 0 && vis[fa] == 0) {
            vis[fa] = 1;
            dfs(step + 1, fa);
        }
        if (l != 0 && vis[l] == 0) {
            vis[l] = 1;
            dfs(step + 1, l);
        }
        if (r != 0 && vis[r] == 0) {
            vis[r] = 1;
            dfs(step + 1, r);
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();

        for (int i = 1; i <= n; i++) {
            t[i] = new TreeNode(sc.nextInt());
            t[i].left = sc.nextInt();
            t[i].right = sc.nextInt();

            if (t[i].left != 0)
                t[t[i].left] = new TreeNode(i);
            if (t[i].right != 0)
                t[t[i].right] = new TreeNode(i);
            if (t[i].left != 0)
                t[t[i].left].father = i;
            if (t[i].right != 0)
                t[t[i].right].father = i;
        }

        for (int i = 1; i <= n; i++) {
            sum = 0;
            for (int j = 0; j < vis.length; j++) {
                vis[j] = 0;
            }
            vis[i] = 1;
            dfs(0, i);
            ans = Math.min(ans, sum);
        }

        System.out.println(ans);
    }
}