#include<iostream>#include<cstdio>#include<cstring>#include<algorithm>#define maxv 200500#define maxe 400500#define inf 0x7f7f7f7f7f7f7f7fLLusing namespace std;int n,x,g[maxv],nume=0,a[maxv],fath[maxv];long long dp[maxv][2];struct edge{    int v,nxt;}e[maxe];void addedge(int u,int v){    e[++nume].v=v;    e[nume].nxt=g[u];    g[u]=nume;}void dfs(int x){       dp[x][0]=0;dp[x][1]=-inf;    for (int i=g[x];i;i=e[i].nxt)    {        int v=e[i].v;        if (v==fath[x]) continue;        fath[v]=x;dfs(v);        long long t0=dp[x][0],t1=dp[x][1];        dp[x][0]=max(t0+dp[v][0],t1+dp[v][1]);        dp[x][1]=max(t0+dp[v][1],t1+dp[v][0]);    }    dp[x][1]=max(dp[x][0]+a[x],dp[x][1]);}int main(){    scanf("%d",&n);    for (int i=1;i<=n;i++)    {        scanf("%d%d",&x,&a[i]);        if (i!=1) {addedge(x,i);addedge(i,x);}    }    dfs(1);    printf("%lld\n",dp[1][1]);    return 0;}