tijie

#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int MOD = 1e9+7;
const int MAXN = 2e5 + 10;
vector<int> g[MAXN];
int sz[MAXN];
ll ipow2[MAXN];
int n;

void dfs(int u, int fa)
{
    sz[u] = 1;
    for(int v : g[u])
    {
        if(v == fa) continue;
        dfs(v, u);
        sz[u] += sz[v];
    }
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    ipow2[0] = 1;
    ll inv2 = 500000004;
    for(int i=1;i<=n;i++)
    {
        ipow2[i] = ipow2[i-1] * inv2 % MOD;
    }
    for(int i=1;i<=n-1;i++)
    {
        int a,b;
        cin >> a >> b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    dfs(1, -1);
    ll ans = 0;
    for(int u=1;u<=n;u++)
    {
        vector<int> comp;
        for(int v:g[u])
        {
            if(sz[v] < sz[u]) comp.push_back(sz[v]);
            else comp.push_back(n - sz[u]);
        }
        ll P0 = ipow2[n-1];
        ll sum = 0;
        for(int s : comp)
        {
            ll term = (1 - ipow2[s] + MOD) % MOD;
            term = term * ipow2[(n-1)-s] % MOD;
            sum = (sum + term) % MOD;
        }
        ll p = ( (1 - P0 + MOD) % MOD - sum + MOD ) % MOD;
        ll contrib = p * inv2 % MOD;
        ans = (ans + contrib) % MOD;
    }
    cout << ans << endl;
    return 0;
}