#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>
using namespace std;
int read(){int z=0,mark=1;  char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')mark=-1;  ch=getchar();}
	while(ch>='0'&&ch<='9'){z=(z<<3)+(z<<1)+ch-'0';  ch=getchar();}
	return z*mark;
}
const long long mo=1000000007;
struct ddd{int next,y;}e[110000];int LINK[110000],ltop=0;
inline void insert(int x,int y){e[++ltop].next=LINK[x];LINK[x]=ltop;e[ltop].y=y;}
int n,a[110000];
long long sum[110000];
long long ans=0;
void dfs(int x){
	sum[x]=0;
	long long bowl=a[x],bowl2=0,bowl3=(((a[x]*a[x])%mo)*a[x])%mo;
	for(int i=LINK[x];i;i=e[i].next){
	  	dfs(e[i].y);
		bowl=(bowl*sum[e[i].y])%mo;
		sum[x]=(sum[x]+sum[e[i].y])%mo;
		bowl2=(bowl2+((sum[e[i].y]*a[x])%mo)*a[x]*2)%mo;
	}
	if(!LINK[x] || !e[LINK[x]].next)  bowl=0;
	sum[x]=(sum[x]+a[x])%mo;
	ans=(ans+bowl+bowl2+bowl3)%mo;
}
int main(){
	//freopen("ddd.in","r",stdin);
	freopen("asm_algo.in","r",stdin);
	freopen("asm_algo.out","w",stdout);
	cin>>n>>a[1];
	int _father;
	for(int i=2;i<=n;i++){
		_father=read(),a[i]=read();
		insert(_father,i);
	}
	dfs(1);
	cout<<ans<<endl;
	return 0;
}