#include <bits/stdc++.h>
using namespace std;
#define TRACE(x) cerr << #x << " :: " << x << endl
#define _ << " " <<
#define SZ(x) (int)(x).size()
#define ALL(x) (x).begin(),(x).end()
#define FOR(i,a,b) for(int i=(a);i<=(b);++i)
#define RFOR(i,a,b) for(int i=(a);i>=(b);--i)
typedef long long ll;
//const int mxN = 2e5+5;
const int mxN = 5e3+5;
const ll inf = 1e18;
int N, A[mxN], H[mxN], C[mxN];
vector<int> al[mxN];
ll dp[mxN][mxN];
void dfs(int u) {
FOR(x,0,u) dp[u][x] = H[x] == H[u] ? 0 : C[u];
for (int v : al[u]) {
dfs(v);
FOR(x,0,u){
dp[u][x] += min(dp[v][x], H[x] <= H[v] ? dp[v][v] : inf);
}
}
}
int main() {
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin >> N;
FOR(i,1,N){
cin >> A[i] >> H[i] >> C[i];
if (i != 1) al[A[i]].push_back(i);
}
H[0] = 1;
dfs(1);
cout << min(dp[1][0], dp[1][1]) << '\n';
}
