typedef long long Int;
typedef vector<int> vint;
typedef pair<int,int> pint;
#define mp make_pair
template<class T> void pv(T a, T b) { for (T i=a; i!=b; ++i) cout << *i << " "; cout << endl; }
template<class T> void pvp(T a, T b) { for (T i=a; i!=b; ++i) cout << "(" << i->first << ", " << i->second << ") "; cout << endl; }
int n,m,ptr[100010],next[100010],zu[100010];
int N;
int A[100010];
int ans;
int saki(int u) {
int ret=A[u],tmp;
for (int i=ptr[u]; ~i; i=next[i]) {
tmp = saki(zu[i]);
if (tmp > 0) ret += tmp;
}
ans = max(ans, ret);
return ret;
}
int main() {
//freopen("committee.in", "r", stdin);
int u,v;
int root=0;
scanf("%i", &N);
n = N; m = 0; memset(ptr, ~0, n<<2);
for (u=0; u<N; ++u) {
scanf("%i%i", &v, &A[u]);
if (v--) {
next[m] = ptr[v]; ptr[v] = m; zu[m] = u; ++m;
} else {
root = u;
}
}
