#include using namespace std; #define int long long #define rep(i,n) for(int (i)=0;(i)<(n);(i)++) #define rrep(i,n) for(int (i)=((n)-1);(i)>=0;(i)--) #define itn int #define miele(v) min_element(v.begin(), v.end()) #define maele(v) max_element(v.begin(), v.end()) #define SUM(v) accumulate(v.begin(), v.end(), 0LL) #define lb(a, key) lower_bound(a.begin(),a.end(),key) #define ub(a, key) upper_bound(a.begin(),a.end(),key) #define COUNT(a, key) count(a.begin(), a.end(), key) #define BITCOUNT(x) __builtin_popcount(x) #define pb push_back #define all(x) (x).begin(),(x).end() #define F first #define S second using P = pair ; using WeightedGraph = vector>; using UnWeightedGraph = vector>; using Real = long double; using Point = complex; //Point and Vector2d is the same! using Vector2d = complex; const long long INF = 1LL << 60; const int MOD = 1000000007; const double EPS = 1e-15; const double PI=3.14159265358979323846; template int getIndexOfLowerBound(vector &v, T x){ return lower_bound(v.begin(),v.end(),x)-v.begin(); } template int getIndexOfUpperBound(vector &v, T x){ return upper_bound(v.begin(),v.end(),x)-v.begin(); } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; } template inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; } #define DUMPOUT cerr #define repi(itr, ds) for (auto itr = ds.begin(); itr != ds.end(); itr++) istream &operator>>(istream &is, Point &p) { Real a, b; is >> a >> b; p = Point(a, b); return is; } template istream &operator>>(istream &is, pair &p_var) { is >> p_var.first >> p_var.second; return is; } template istream &operator>>(istream &is, vector &vec) { for (T &x : vec) is >> x; return is; } template ostream &operator<<(ostream &os, pair &pair_var) { DUMPOUT<<'{'; os << pair_var.first; DUMPOUT<<','; os << " "<< pair_var.second; DUMPOUT<<'}'; return os; } template ostream &operator<<(ostream &os, vector &vec) { DUMPOUT<<'['; for (int i = 0; i < vec.size(); i++) os << vec[i] << (i + 1 == vec.size() ? "" : " "); DUMPOUT<<']'; return os; } template ostream &operator<<(ostream &os, vector> &df) { for (auto& vec : df) os< ostream &operator<<(ostream &os, map &map_var) { DUMPOUT << "{"; repi(itr, map_var) { os << *itr; itr++; if (itr != map_var.end()) DUMPOUT << ", "; itr--; } DUMPOUT << "}"; return os; } template ostream &operator<<(ostream &os, set &set_var) { DUMPOUT << "{"; repi(itr, set_var) { os << *itr; itr++; if (itr != set_var.end()) DUMPOUT << ", "; itr--; } DUMPOUT << "}"; return os; } void print() {cout << endl;} template void print(Head&& head, Tail&&... tail) { cout << head; if (sizeof...(tail) != 0) cout << " "; print(forward(tail)...); } void dump_func() {DUMPOUT << '#'< void dump_func(Head &&head, Tail &&... tail) { DUMPOUT << head; if (sizeof...(Tail) > 0) DUMPOUT << ", "; dump_func(std::move(tail)...); } #ifdef DEBUG_ #define DEB #define dump(...) \ DUMPOUT << " " << string(#__VA_ARGS__) << ": " \ << "[" << to_string(__LINE__) << ":" << __FUNCTION__ << "]" \ << endl \ << " ", \ dump_func(__VA_ARGS__) #else #define DEB if (false) #define dump(...) #endif template struct Fp { long long val; constexpr Fp(long long v = 0) noexcept : val(v % MOD) { if (val < 0) val += MOD; } constexpr int getmod() { return MOD; } constexpr Fp operator - () const noexcept { return val ? MOD - val : 0; } constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; } constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; } constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; } constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; } constexpr Fp& operator += (const Fp& r) noexcept { val += r.val; if (val >= MOD) val -= MOD; return *this; } constexpr Fp& operator -= (const Fp& r) noexcept { val -= r.val; if (val < 0) val += MOD; return *this; } constexpr Fp& operator *= (const Fp& r) noexcept { val = val * r.val % MOD; return *this; } constexpr Fp& operator /= (const Fp& r) noexcept { long long a = r.val, b = MOD, u = 1, v = 0; while (b) { long long t = a / b; a -= t * b; swap(a, b); u -= t * v; swap(u, v); } val = val * u % MOD; if (val < 0) val += MOD; return *this; } constexpr bool operator == (const Fp& r) const noexcept { return this->val == r.val; } constexpr bool operator != (const Fp& r) const noexcept { return this->val != r.val; } friend constexpr ostream& operator << (ostream &os, const Fp& x) noexcept { return os << x.val; } friend constexpr Fp modpow(const Fp &a, long long n) noexcept { if (n == 0) return 1; auto t = modpow(a, n / 2); t = t * t; if (n & 1) t = t * a; return t; } }; using mint = Fp<1000000007>; int n; UnWeightedGraph g; vector > daten; vector done; pair dfs(int now, int mae = -1, int cnt=0){ if(done[now]) return daten[now]; daten[now].S += 1; for(auto e: g[now]){ daten[now].F += dfs(e, now).F + dfs(e, now).S; daten[now].S += dfs(e, now).S; } done[now] = 1; return daten[now]; } signed main(void) { cin.tie(0); ios::sync_with_stdio(false); cin>>n; g.resize(n); daten.resize(n), done.resize(n); rep(i, n-1){ int a, b; cin>>a>>b; a--, b--; g[a].pb(b); // a to b } mint ans = 0; for(int i=0;i