#include using lint=long long; using real=long double; lint mod=1'000'000'007; lint inverse(lint x){ lint y=1,u=mod,v=0; while(x){ lint q=u/x; u-=q*x;std::swap(x,u); v-=q*y;std::swap(y,v); } assert(x==0&&std::abs(y)==mod&&std::abs(u)==1&&std::abs(v)>n; std::vector>g(n); for(lint i=0;i>u>>v;u--,v--; g.at(u).push_back(v); g.at(v).push_back(u); } std::vectordepth(n,-1); std::vectorque={0}; depth.at(0)=0; for(lint i=0;i<(lint)que.size();i++){ lint x=que.at(i); for(lint y:g.at(x)){ if(depth.at(y)!=-1)continue; depth.at(y)=depth.at(x)+1; que.push_back(y); } } lint ans=std::accumulate(depth.begin(),depth.end(),0ll, [](lint acc,lint x){return acc+inverse(x+1);})%mod; if(ans<0)ans+=mod; for(lint i=1;i<=n;i++)ans=ans*i%mod; std::cout<