#include<bits/stdc++.h>
        
using namespace std;

int n;
int f[15][15];
long long Max = -1e9, all;

struct node
{
    bool flag;
    bool flag2;
    vector<int> son;
    vector<int> w;
};

vector<node> v(100005);

inline bool dfs2(int step, int aim)
{
    if(step == aim)
        return true;
    for (int i = 0; i < v[step].son.size(); ++i)
    {
        if(f[step][v[step].son[i]] == 0 && v[v[step].son[i]].flag2 == true)
        {
            v[v[step].son[i]].flag2 = false;
            bool pd = dfs2(v[step].son[i],aim);
            v[v[step].son[i]].flag2 = true;
            if(pd == true)
                return true;
        }
    }
    return false;
}

inline long long Count()
{
    long long ans = 0;
    for (int i = 1; i <= n; ++i)
        for (int j = i+1; j <= n; ++j)
            ans += dfs2(i,j);
    return ans;
}

inline void dfs(int step, long long cnt, int aim)
{
    if(step == aim)
    {
        Max = max(Max,all-Count()-cnt);
        //cout << Count() << " " << cnt << '\n';
        return;
    }
    for (int i = 0; i < v[step].son.size(); ++i)
    {
        if(v[v[step].son[i]].flag == true)
        {
            v[v[step].son[i]].flag = false;
            dfs(v[step].son[i],cnt,aim);
            f[step][v[step].son[i]] = 1;
            f[v[step].son[i]][step] = 1;
            dfs(v[step].son[i],cnt+v[step].w[i],aim);
            f[step][v[step].son[i]] = 0;
            f[v[step].son[i]][step] = 0;
            v[v[step].son[i]].flag = true;
        }
    }
} 
        
int main()
{
    freopen("delete.in", "r", stdin);
   	freopen("delete.out", "w", stdout);
           	
    ios::sync_with_stdio(false);
   	cin.tie(0); cout.tie(0);
        
    memset(f,0,sizeof(f));
    cin >> n;
    all = n*(n-1)/2;
    
    for (int i = 2; i <= n; ++i)
    {
        int p, w;
        cin >> p >> w;
        v[p].son.push_back(i);
        v[i].son.push_back(p);
        v[p].w.push_back(w);
        v[i].w.push_back(w);
    }
    for (int i = 1; i <= n; ++i)
        v[i].flag = true;
    for (int i = 1; i <= n; ++i)
        v[i].flag2 = true;
    for (int i = 1; i <= n; ++i)
        for (int j = i+1; j <= n; ++j)
            dfs(i,0,j);
    
    cout << Max;
        	
   	return 0;
}