#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cmath>
#define ll long long
#define rt 1
using namespace std;
const int MN=1e6+5;
const int mod=1e9+7;
ll n,head[MN],tot,deep[MN],fa[MN][25],ans;
struct edge{ll to,nxt;}e[MN<<2];
void write(ll n){if(n<0){putchar('-');write(-n);return;}if(n>9)write(n/10);putchar(n%10+'0');}
ll read(){ll x=0,f=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}while(ch>='0'&&ch<='9'){x=(x<<1)+(x<<3)+(ch^48);ch=getchar();}return x*f;}
void add(ll u, ll v){e[++tot].nxt=head[u];head[u]=tot;e[tot].to=v;}
void lca_dfs(ll u, ll f){
    deep[u]=deep[f]+1;fa[u][0]=f;
    for(int i=1; i<25; i++) fa[u][i]=fa[fa[u][i-1]][i-1];
    for(int i=head[u]; i; i=e[i].nxt){
        ll v=e[i].to;
        if(v==f) continue;
        lca_dfs(v,u);
    }
}
ll lca(ll x, ll y){
    if(deep[x]<deep[y]) swap(x,y);
    for(int i=24; i>=0; i--) if(deep[x]-(1<<i)>=deep[y]) x=fa[x][i];
    if(x==y) return x;
    for(int i=24; i>=0; i--) if(fa[x][i]!=fa[y][i]) x=fa[x][i],y=fa[y][i];
    return fa[x][0];
}
int main(){
    n=read();
    for(int i=1; i<n; i++){
        ll u=read(),v=read();
        add(u,v);add(v,u);
    }
    lca_dfs(rt,0);
    for(int i=1; i<n; i++) for(int j=i+1; j<=n; j++) ans=(ans+i*j%mod*(deep[i]+deep[j]-2*deep[lca(i,j)])%mod)%mod;
    write(ans);putchar('\n');
    return 0;
}