#include<cstdio>

#include<algorithm>

#include<cstring>

#include<cmath>

#include<iostream>

#include<cctype>

#include<set>

#include<vector>

#include<queue>

#include<map>

#define fi(s) freopen(s,"r",stdin);

#define fo(s) freopen(s,"w",stdout);

using namespace std;

typedef long long LL;

inline int read() {

    int x=,f=;char ch=getchar();for(;!isdigit(ch);ch=getchar())if(ch=='-')f=-;

    for(;isdigit(ch);ch=getchar())x=x*+ch-'';return x*f;

}

const int N = ;

int head[N], ls[N], rs[N], a[N], b[N], c[N], siz0[N], siz1[N], n;

LL dp[][][];

inline LL Calc(int u,int x,int y) { // 从根到u的路径上，表示翻新了x条公路，y条铁路

    if (u >= n) return 1ll * c[u] * (siz0[u] - x + a[u]) * (siz1[u] - y + b[u]);

    return dp[u][x][y];

}

void dfs(int u) {

    if (u >= n) { return ;

//        for (int i = 0; i <= siz0[u]; ++i)

//            for (int j = 0; j <= siz1[u]; ++j)

//                dp[u][i][j] = 1ll * c[u] * (siz0[u] - i + a[u]) * (siz1[u] - j + b[u]); // 表示翻新了i条公路，j条铁路

//        return ;

    }

    siz0[ls[u]] = siz0[u] + ; siz1[ls[u]] = siz1[u]; dfs(ls[u]);

    siz0[rs[u]] = siz0[u]; siz1[rs[u]] = siz1[u] + ; dfs(rs[u]);

    for (int i = ; i <= siz0[u]; ++i)

        for (int j = ; j <= siz1[u]; ++j) {

            dp[u][i][j] = 1e18;

            dp[u][i][j] = min(dp[u][i][j], Calc(ls[u], i + , j) + Calc(rs[u], i, j)); // 翻新公路

            dp[u][i][j] = min(dp[u][i][j], Calc(ls[u], i, j) + Calc(rs[u], i, j + )); // 翻新铁路

        }

}

int main() {

    n = read();

    for (int i = ; i < n; ++i) {

        int u = read(), v = read();

        if (u < ) u = -u + n - ;

        if (v < ) v = -v + n - ;

        ls[i] = u;

        rs[i] = v;

    }

    for (int i = ; i <= n; ++i)

        a[i + n - ] = read(), b[i + n - ] = read(), c[i + n - ] = read();

    dfs();

    cout << dp[][][];

    return ;

}