/* #region header */ #ifdef LOCAL #include "/Users/takakurashokichi/Desktop/atcoder/cxx-prettyprint-master/prettyprint.hpp" #define debug(x) cout << x << endl #else #define debug(...) 42 #endif #pragma GCC optimize("Ofast") #include //types using namespace std; using ll = long long; using ull = unsigned long long; using ld = long double; typedef pair < ll , ll > Pl; typedef pair < int, int > Pi; typedef vector vl; typedef vector vi; typedef vector vc; template< typename T > using mat = vector< vector< T > >; typedef vector> vvi; typedef vector> vvl; typedef vector> vvc; template< int mod > struct modint { int x; modint() : x(0) {} modint(int64_t y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {} modint &operator+=(const modint &p) { if((x += p.x) >= mod) x -= mod; return *this; } modint &operator-=(const modint &p) { if((x += mod - p.x) >= mod) x -= mod; return *this; } modint &operator*=(const modint &p) { x = (int) (1LL * x * p.x % mod); return *this; } modint &operator/=(const modint &p) { *this *= p.inverse(); return *this; } modint operator-() const { return modint(-x); } modint operator+(const modint &p) const { return modint(*this) += p; } modint operator-(const modint &p) const { return modint(*this) -= p; } modint operator*(const modint &p) const { return modint(*this) *= p; } modint operator/(const modint &p) const { return modint(*this) /= p; } bool operator==(const modint &p) const { return x == p.x; } bool operator!=(const modint &p) const { return x != p.x; } modint inverse() const { int a = x, b = mod, u = 1, v = 0, t; while(b > 0) { t = a / b; swap(a -= t * b, b); swap(u -= t * v, v); } return modint(u); } modint pow(int64_t n) const { modint ret(1), mul(x); while(n > 0) { if(n & 1) ret *= mul; mul *= mul; n >>= 1; } return ret; } friend ostream &operator<<(ostream &os, const modint &p) { return os << p.x; } friend istream &operator>>(istream &is, modint &a) { int64_t t; is >> t; a = modint< mod >(t); return (is); } static int get_mod() { return mod; } }; //abreviations #define all(x) (x).begin(), (x).end() #define rall(x) (x).rbegin(), (x).rend() #define rep_(i, a_, b_, a, b, ...) for (int i = (a), max_i = (b); i < max_i; i++) #define rep(i, ...) rep_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__) #define rrep_(i, a_, b_, a, b, ...) for (int i = (b-1), min_i = (a); i >= min_i; i--) #define rrep(i, ...) rrep_(i, __VA_ARGS__, __VA_ARGS__, 0, __VA_ARGS__) #define SZ(x) ((int)(x).size()) #define pb(x) push_back(x) #define eb(x) emplace_back(x) #define mp make_pair #define print(x) cout << x << endl #define vprint(x) rep(i, x.xize())cout << x[i] << ' '; cout << endl #define vsum(x) accumulate(all(x), 0LL) #define vmax(a) *max_element(all(a)) #define vmin(a) *min_element(all(a)) #define lb(c, x) distance((c).begin(), lower_bound(all(c), (x))) #define ub(c, x) distance((c).begin(), upper_bound(all(c), (x))) //functions //gcd(0, x) fails. ll gcd(ll a, ll b) { return b ? gcd(b, a%b) : a; } ll lcm(ll a, ll b) { return a/gcd(a, b)*b;} templatebool chmax(T &a, const T &b) { if (abool chmin(T &a, const T &b) { if (b T mypow(T x, ll n) { T ret = 1; while(n > 0) { if(n & 1) (ret *= x); (x *= x); n >>= 1; } return ret; } ll modpow(ll x, ll n, const ll mod) { ll ret = 1; while(n > 0) { if(n & 1) (ret *= x); (x *= x); n >>= 1; x%=mod; ret%=mod; } return ret; } uint64_t my_rand(void) { static uint64_t x = 88172645463325252ULL; x = x ^ (x << 13); x = x ^ (x >> 7); return x = x ^ (x << 17); } int popcnt(ull x) { return __builtin_popcountll(x); } //graph template template< typename T > struct edge { int src, to; T cost; edge(int to, T cost) : src(-1), to(to), cost(cost) {} edge(int src, int to, T cost) : src(src), to(to), cost(cost) {} edge &operator=(const int &x) { to = x; return *this; } bool operator<(const edge &r) const { return cost < r.cost; } operator int() const { return to; } }; template< typename T > using Edges = vector< edge< T > >; template< typename T > using WeightedGraph = vector< Edges< T > >; using UnWeightedGraph = vector< vector< int > >; struct Timer { clock_t start_time; void start() { start_time = clock(); } int lap() { //return x ms. return (clock()-start_time)*1000 / CLOCKS_PER_SEC; } }; /* #endregion*/ //constant #define inf 1000000005 #define INF 4000000004000000000LL #define mod 1000000007LL #define endl '\n' typedef modint mint; const long double eps = 0.000001; const long double PI = 3.141592653589793; //library mat sub; Pl dfs(mat& g, int v){ ll res = 0; ll count = 1; for(int nv:g[v]){ auto [c, s] = dfs(g, nv); sub[v].pb(mp(c, s)); res+=s; count+=c; } res+=count; return mp(count, res); } int main(){ cin.tie(0); ios::sync_with_stdio(0); cout << setprecision(20); int n; cin>>n; sub.resize(n); mat g(n); vi deg(n); rep(i, n-1){ int a, b; cin>>a>>b; a--;b--; g[a].pb(b); deg[b]++; } int root; rep(i, n){ if(deg[i]==0)root = i; } dfs(g, root); mint ans = 0; rep(i, n){ for(auto s:sub[i]){ ans+=s.second; } } print(ans); }