
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cstdint>
#include <cmath>
#include <iostream>
#include <set>
#include <string>
#include <queue>
#include <utility>
#include <vector>

using namespace std;

constexpr static int MOD = 1e9 + 7;
constexpr static int MAXN = 250;

int n;
vector <int> adj[MAXN];
int d[MAXN][MAXN];
int64_t ev[MAXN][MAXN];

void solve() {
    cin >> n;
    for (int i = 0; i < n - 1; i++) {
        int u, v;
        cin >> u >> v;
        u--, v--;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    for (int i = 0; i < n; i++)
        for (int j = 0; j < n; j++)
            d[i][j] = n;
    for (int i = 0; i < n; i++) {
        d[i][i] = 0;
        for (int j : adj[i])
            d[i][j] = 1;
    }
    for (int k = 0; k < n; k++)
        for (int i = 0; i < n; i++)
            for (int j = 0; j < n; j++)
                if (d[i][k] + d[k][j] < d[i][j])
                    d[i][j] = d[i][k] + d[k][j];

    vector <int64_t> inv(n + 1);
    inv[1] = 1;
    for (int i = 2; i <= n; i++)
        inv[i] = MOD - (MOD / i) * inv[MOD % i] % MOD;

    for (int i = 1; i <= n; i++) {
        ev[i][0] = 1;
        for (int j = 1; j < i; j++) {
            ev[i][j] = (ev[i - 1][j - 1] + ev[i - 1][j]) * inv[2] % MOD;
        }
        ev[i][i] = 0;
    }

    int64_t total = 0;
    for (int i = 0; i < n; i++) {
        for (int j = i + 1; j < n; j++) {
            total += inv[n];
            for (int k = 0; k < n; k++) {
                if (k == i || k == j) {
                    continue;
                }
                else if (d[k][i] + d[i][j] == d[k][j]) {
                    total += 0;
                }
                else if (d[k][j] + d[i][j] == d[k][i]) {
                    total += inv[n];
                }
                else { // (d[k][i] + d[k][j] == d[i][j])
                    int diff = d[k][j] - d[k][i];
                    int len = d[i][j];
                    // x + y == len
                    // x - y = diff
                    // x = (len + diff) / 2;
                    int x = (len + diff) / 2;
                    total = (total + ev[len][x] * inv[n]) % MOD;
                }
            }
        }
    }
    total %= MOD;
    cout << total << '\n';
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    solve();
}
