#include<cstdio>
#include<deque>
#include<iostream>
using namespace std;
typedef long long LL;
const int SIZEN=100010,MOD=1000000007;
int n;
LL w[SIZEN];
LL sum[SIZEN]={0};//以i为根的子树权值之和
LL ans=0;
deque<int> s[SIZEN];
void read()
{
	scanf("%d%lld",&n,&w[1]);
	int p;
	for(int i=2;i<=n;i++)
	{
		scanf("%d%lld",&p,&w[i]);
		s[p].push_back(i);
	}
}
void DP(int x)
{
	sum[x]=w[x];
	for(int i=0;i<s[x].size();i++)
	{
		int v=s[x][i];
		DP(v);
		LL now=sum[v];
		ans+=(((sum[x]*now*2)%MOD)*w[x])%MOD;
		//cout<<v<<" "<<now<<" "<<sum[x]<<" "<<ans<<" "<<endl;
		sum[x]+=sum[v];
		sum[x]%=MOD;
		ans%=MOD;
	}
	ans+=(((w[x]*w[x])%MOD)*w[x])%MOD;
}
void work()
{
	DP(1);
	//for(int i=1;i<=n;i++) cout<<sum[i]<<endl;
	printf("%lld",ans);
}
int main()
{
	freopen("asm_algo.in","r",stdin);
	freopen("asm_algo.out","w",stdout);
	read();
	work();
	return 0;
}