#include <bits/stdc++.h>
using namespace std;
int main() {
ios::sync_with_stdio(false);
cin.tie(0);
int n;
cin >> n;
vector<vector<pair<int, int>>> g(n);
for (int i = 0; i < n; i++) {
int to, w;
cin >> to >> w;
--to;
g[i].emplace_back(to, w);
g[to].emplace_back(i, w);
}
vector<int> vis(n, 0);
vector<int> nm;
function<void(int)> mark_comp_vis = [&](int v) {
vis[v] = 1;
nm.push_back(v);
for (auto [u, w] : g[v]) {
if (vis[u]) {
continue;
}
mark_comp_vis(u);
}
};
vector<int> cyc;
vector<int> stk;
function<bool(int, int)> get_cyc = [&](int v, int pr) {
stk.push_back(v);
vis[v] = 1;
int ccc = 0;
for (auto [u, w] : g[v]) {
ccc += (u == pr);
}
if (ccc == (int) g[v].size()) {
while (!stk.empty()) {
cyc.push_back(stk.back());
if (stk.back() == pr) {
break;
}
stk.pop_back();
}
return true;
}
for (auto [u, w] : g[v]) {
if (u == pr) {
continue;
}
if (vis[u]) {
while (!stk.empty()) {
cyc.push_back(stk.back());
if (stk.back() == u) {
break;
}
stk.pop_back();
}
return true;
}
if (get_cyc(u, v)) {
return true;
}
}
stk.pop_back();
return false;
};
vector<long long> d(n);
function<void(int, int)> calc_dists = [&](int v, int pr) {
d[v] = 0;
for (auto [u, w] : g[v]) {
if (u == pr || vis[u]) {
continue;
}
d[v] = max(d[v], w + d[u]);
calc_dists(u, v);
}
};
long long res = 0;
for (int i = 0; i < n; i++) {
if (!vis[i]) {
nm.clear();
mark_comp_vis(i);
for (int v : nm) {
vis[v] = 0;
}
cyc.clear();
stk.clear();
get_cyc(i, -1);
for (int v : nm) {
vis[v] = 0;
}
for (int v : cyc) {
vis[v] = 1;
}
long long ans = 0;
for (int v : cyc) {
calc_dists(v, -1);
}
long long cyclen = 0;
for (int v : cyc) {
for (auto [u, w] : g[v]) {
if (vis[u]) {
cyclen += w;
}
}
}
cyclen >>= 1;
for (int v : cyc) {
for (auto [u, w] : g[v]) {
if (vis[u]) {
ans = max(ans, d[v] + cyclen - w);
}
}
}
for (int k = 1; k < (int) cyc.size(); k++) {
int v = cyc[k];
long long dvu = 0;
for (int j = k - 1; j >= 0; j--) {
for (auto [u, w] : g[v]) {
if (u == cyc[j]) {
dvu += w;
break;
}
}
ans = max(ans, d[v] + d[cyc[j]] + max(dvu, cyclen - dvu));
}
}
res += ans;
for (int v : nm) {
vis[v] = 1;
}
}
}
cout << res << '\n';
return 0;
}
