#include <iostream>
#include <vector>
#include <bits/stdc++.h>
using namespace std;
const int maxn = 3e5 + 10;
vector<int> graph[maxn];
int rating[maxn];
int parent[maxn];
int dp[maxn];
int dfs(int node) {
    if(dp[node] != -1) {
        return dp[node];
    }
    
    int taken = rating[node];
    for(int i = 0; i < (int) graph[node].size(); i++) {
        int neighbour = graph[node][i];
        for(int j = 0; j < (int) graph[neighbour].size(); j++) {
            int neighbour_of_neighbour = graph[neighbour][j];
            taken += dfs(neighbour_of_neighbour);
        }
    }
    int not_taken = 0;
    for(int i = 0; i < (int) graph[node].size(); i++) {
        int neighbour = graph[node][i];
        not_taken += dfs(neighbour);
    }
    return dp[node] = max(taken, not_taken);
}
int main() {
    ios_base::sync_with_stdio(false);
    memset(dp, -1, sizeof dp);
    int n;
    cin >> n;
    cin >> rating[0];
    for(int i = 1; i < n; i++) {
        int p;
        cin >> rating[i] >> p;
        parent[i] = p;
        graph[p].push_back(i);
        
    }
    cout << dfs(0) << endl;
   return 0;
}
/*
 7
 1 2
 1 3
 2 4
 2 5
 3 6
 3 7
 **/