#include<bits/stdc++.h>
using namespace std;
using ll = long long;
#define F first
#define S second
template<typename T, typename U>
ostream &operator<<(ostream &os, const pair<T, U> &p)
{
return os << "(" << p.F << "," << p.S << ")";
}
template<typename T>
void print(T v)
{
for(auto x : v)
cout << x << " ";
cout << "\n";
}
int w[300005];
int p[300005];
vector<int> adj[300005];
int main()
{
ll n, s;
cin >> n;
ll sum = 0, mx = s;
for(int i = 1; i <= n; i++)
{
cin >> w[i] >> p[i];
adj[p[i]].push_back(i);
sum += w[i];
}
using node = pair<int, int>;
priority_queue<node, vector<node>, greater<>> q;
for(int i = 1; i <= n; i++)
{
if(adj[i].size() == 0) q.emplace(w[i], i);
}
while(!q.empty())
{
mx = max(mx, sum);
auto [cost, i] = q.top(); q.pop();
sum -= cost;
if(p[i] != 0)
{
q.emplace(w[p[i]], p[i]);
}
}
cout << mx << "\n";
}
