#include <cstdlib>
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <map>
#include <stack>
#include <vector>
#include <map>
#include <queue>
#include <ctime>
#include <algorithm>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef unsigned int uint;
const int inf=1061109567;
const int maxn=100010;
const int maxm=100010;
const int mod=1000000007;
const double pi=3.14;

vector<int> G[maxn];
ll sum[maxn];
ll w[maxn],ans=0;

void build_tree(int u)
{
    int len=G[u].size();
    ll tmp1=0,tmp2=0;
    for(int i=0;i<len;i++)
    {
        int v=G[u][i];
        build_tree(v);
        sum[u]+=sum[v];
        tmp1+=sum[v];
        tmp2+=(sum[v]*sum[v])%mod;
        tmp1%=mod;tmp2%=mod;
    }
    sum[u]+=w[u];
    ans+=(((((w[u]*w[u])%mod)*tmp1)%mod)*2)%mod;
    ans%=mod;tmp1=(tmp1*tmp1)%mod;
    ans+=w[u]*(tmp1-tmp2);ans%=mod;
}

int main()
{
    freopen("asm_algo.in","r",stdin);
    freopen("asm_algo.out","w",stdout);
    //clock_t st=clock();
    int n,p;scanf("%d%d",&n,&w[1]);
    ans+=(((w[1]*w[1])%mod)*w[1])%mod;ans%=mod;
    for(int i=2;i<=n;i++)
    {
        scanf("%d%d",&p,&w[i]);
        G[p].push_back(i);
        ans+=(((w[i]*w[i])%mod)*w[i])%mod;ans%=mod;
    }
    build_tree(1);
    printf("%lld\n",ans%mod);
    //clock_t ed=clock();
    //printf("\nTime used : %.5lf Ms\n",double(ed-st)/CLOCKS_PER_SEC);
    return 0;
}