#define _CRT_SECURE_NO_WARNINGS
#include <vector>
#include <string>
#include <iostream>
#include <algorithm>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <fstream>
#include <map>
#include <set>
#include <queue>
#include <memory.h>
#include <time.h>
#include <iostream>
#include <string>
#include <cstring>
#include <vector>
#include <cmath>
#include <map>
#include <algorithm>
#include <cstdio>
#include <set>
#include <queue>
#include <cassert>
#include <climits>
#define sz(x) int((x).size())
#define FOR(i,a,b) for(ll(i) = (a); (i) <= (b); ++(i))
#define ROF(i,a,b) for(ll(i) = (a); (i) >= (b); --(i))
#define rep(i,n) for (int(i) = 0; (i) < (n); ++(i))
#define fe(i,a) for (ll(i) = 0; (i) < int((a).size()); ++(i))
#define C(a) memset((a),0,sizeof(a))
#define pb push_back
#define ppb pop_back
#define all(c) (c).begin(), (c).end()
#define sqr(a) (a)*(a)
#define mp(a,b) make_pair((a), (b))
#define X first
#define Y second
#define file freopen("input.txt","r",stdin)
#define file2 freopen("output.txt", "w",stdout)
#define text freopen("input.txt","r",stdin); freopen("output.txt", "w",stdout)
using namespace std;
typedef vector<int> vint;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> pii;
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cstring>
#include <string>
#include <vector>
#include <climits>
#include <cassert>
#define y1 vamdlsfmvldf
using namespace std;
const ll mod = (ll)1e9 + 7;
const ll INF = (ll)(1e17);
const int N = 200005;
int parent[N];
int sum[N];
int main(){
   int n;
   cin >> n;
   long long ans = 0;
   for(int i = 0; i < n; ++i){
       int x, t;
       scanf("%d %d", &t, &x);
       if(x == 0){
           sum[i + 1] = sum[parent[t]];
           parent[i + 1] = parent[parent[t]];
       }
       else{
           sum[i + 1] = sum[t] + x;
           parent[i + 1] = t;
       }
       ans += sum[i + 1];
   }
   cout << ans << endl;
   return 0;
}