#include <iostream>
#include <queue>
#define MAX 100010
using namespace std;

int dp[MAX][2], Sum[MAX];
int BB, i, j, n;


struct emp{
	int id, val, boss;
	emp(int i, int v, int b){
		id = i; val = v; boss = b;
	}
};

vector <emp> sons;
vector <int> son_values[MAX];


int find(int father){
	int sum = 0;
	for(int k = 0; k < son_values[father].size();k++)
		sum += dp[k][0];
	//cout << "Sum = "<<sum<<endl;
	return sum;
}

int findI(int father){
	int sum = 0;
	for(int k = 0; k < son_values[father].size();k++)
		sum += max(dp[k][1],dp[k][0]);
	//cout << "Sum = "<<sum<<endl;
	return sum;
}

int main(){
	cin >> n;
	cin >> BB;
	sons.push_back(emp(0,BB,-1));
	for(i=1;i<=n-1;i++){
		int boss, val;
		cin >> boss >>val;
		son_values[boss].push_back(val);
		sons.push_back(emp(i,val,boss));
	}

	dp[n-1][1]=BB;dp[n-1][0]=0;
	for(i=n-2;i>=0;i--){
		dp[i][1]= find(i);
		dp[i][0]= findI(i);
	}

	/*for(i=0;i<=n;i++){
		for(j=0;j<2;j++){
			cout<<dp[i][j]<<" ";
		}
		cout<<endl;
	}*/
	return 0;
}