//#define _GLIBCXX_DEBUG #include using namespace std; #define endl '\n' #define lfs cout<= (ll)(n); i--) using ll = long long; using ld = long double; const ll MOD1 = 1e9+7; const ll MOD9 = 998244353; const ll INF = 1e18; using P = pair; template bool chmin(T1 &a,T2 b){if(a>b){a=b;return true;}else return false;} template bool chmax(T1 &a,T2 b){if(a void ans(bool x,T1 y,T2 z){if(x)cout< void debug(vector>&v,ll h,ll w){for(ll i=0;i&v,ll h,ll w){for(ll i=0;i void debug(vector&v,ll n){if(n!=0)cout< vector>vec(ll x, ll y, T w){ vector>v(x,vector(y,w));return v;} ll gcd(ll x,ll y){ll r;while(y!=0&&(r=x%y)!=0){x=y;y=r;}return y==0?x:y;} vectordx={1,-1,0,0,1,1,-1,-1}; vectordy={0,0,1,-1,1,-1,1,-1}; template vector make_v(size_t a,T b){return vector(a,b);} template auto make_v(size_t a,Ts... ts){ return vector(a,make_v(ts...)); } template ostream &operator<<(ostream &os, const pair&p){ return os << p.first << " " << p.second; } //mt19937 mt(chrono::steady_clock::now().time_since_epoch().count()); 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; } }; using modint = ModInt< MOD1 >;modint pow(ll n, ll x){return modint(n).pow(x);}modint pow(modint n, ll x){return n.pow(x);} //using modint=ld; vectortsort(vector>&g){ ll n = g.size(); vectorret(n),ret2(n); vectorv(n); for(ll i=0;ist; for(ll i=0;i();//閉路がある ll x=st.top(); st.pop(); ret[x]=i; ret2[i]=x; for(ll j=0;j>n; vector>g(n); rep(i,0,n-1){ ll a,b;cin>>a>>b;a--;b--; g[a].PB(b); } auto v=tsort(g); modint ret=0; vectorsz(n,1); auto dfs=[&](auto &&f,ll k,ll d)->void{ for(auto to:g[k]){ f(f,to,d+1); sz[k]+=sz[to]; ret+=sz[to]*d; } }; dfs(dfs,v[0],1); cout<