#include <bits/stdc++.h>
using namespace std;
const int Nmax = 1e5 + 5;
typedef long long ll;
int to[Nmax], cost[Nmax], mx1[Nmax], mx2[Nmax];
vector<int> v[Nmax];
ll ans = 0;
int used[Nmax];
int in_solve, in_cycle;
int n;
void upd(int &mx1, int &mx2, int cost)
{
if(cost >= mx1) mx2 = mx1, mx1 = cost;
else if(cost > mx2) mx2 = cost;
}
void mark(int node)
{
used[node] = 2;
for(auto it : v[node])
if(used[it] != 2)
mark(it);
}
int solve(int node)
{
++in_solve;
while(!used[node])
{
used[node] = 1;
node = to[node];
}
mark(node);
int start = node;
int ans = 2e9;
do
{
if(mx1[to[node]] > cost[node])
ans = 0;
else ans = min(ans, mx1[to[node]] - mx2[to[node]]);
node = to[node];
++in_cycle;
}
while(node != start);
return ans;
}
int main()
{
// freopen("input", "r", stdin);
cin.tie(0); cin.sync_with_stdio(false);
cin >> n;
int i;
for(i=1; i<=n; ++i)
{
cin >> to[i] >> cost[i];
v[to[i]].push_back(i);
}
for(i=1; i<=n; ++i)
upd(mx1[to[i]], mx2[to[i]], cost[i]);
for(i=1; i<=n; ++i)
if(!used[i])
ans += solve(i);
for(i=1; i<=n; ++i) ans += cost[i] - mx1[i];
if(in_cycle == n && in_solve == 1) ans = 0;
cout << ans << '\n';
return 0;
}
