#include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #define ll long long #define int long long #define rep(s,i,n) for(int i=s;i>n; #define sc(s) string s;cin>>s; #define mod 998244353 #define inf 2000000000000000007 #define f first #define s second #define mini(c,a,b) *min_element(c+a,c+b) #define maxi(c,a,b) *max_element(c+a,c+b) #define pi 3.141592653589793238462643383279 #define e_ 2.718281828459045235360287471352 #define P pair #define upp(a,n,x) upper_bound(a,a+n,x)-a; #define low(a,n,x) lower_bound(a,a+n,x)-a; #define UF UnionFind #define pb push_back //printf("%.12Lf\n",); int keta(int x) { rep(0, i, 30) { if (x < 10) { return i + 1; } x = x / 10; } } int gcd(int x, int y) { if (x == 0 || y == 0)return x + y; int aa = x, bb = y; rep(0, i, 1000) { aa = aa % bb; if (aa == 0) { return bb; } bb = bb % aa; if (bb == 0) { return aa; } } } int lcm(int x, int y) { int aa = x, bb = y; rep(0, i, 1000) { aa = aa % bb; if (aa == 0) { return x / bb * y; } bb = bb % aa; if (bb == 0) { return x / aa * y; } } } bool prime(int x) { if (x == 1)return false; rep(2, i, sqrt(x) + 1) { if (x % i == 0 && x != i) { return false; } } return true; } int max(int a, int b) { if (a >= b)return a; else return b; } string maxst(string s, string t) { int n = s.size(); int m = t.size(); if (n > m)return s; else if (n < m)return t; else { rep(0, i, n) { if (s[i] > t[i])return s; if (s[i] < t[i])return t; } return s; } } int min(int a, int b) { if (a >= b)return b; else return a; } int yakuwa(int n) { int sum = 0; rep(1, i, sqrt(n + 1)) { if (n % i == 0)sum += i + n / i; if (i * i == n)sum -= i; } return sum; } int poow(int n,int m){ int pro=1; int nn=n; while(m){ if(m%2==1)pro=pro*nn%mod; m=m/2; nn=nn*nn%mod; } return pro; } int poow2(int n,int m,int modulo){ int pro=1; int nn=n; while(m){ if(m%2==1)pro=pro*nn%modulo; m=m/2; nn=nn*nn%modulo; } return pro; } int inv(int n,int m){ int t=poow(m,mod-2)%mod; return n*t%mod; } int com(int n,int m){ if(n par; UnionFind(int n):par(n){ rep(0,i,n)par[i]=i; } int root(int x){ if (par[x]==x)return x; return par[x]=root(par[x]); } void unite(int x,int y){ int rx=root(x); int ry=root(y); if (rx==ry) return; par[rx]=ry; } bool same(int x,int y){ int rx=root(x); int ry=root(y); return rx==ry; } }; int dijkstraa[514514]; void dijkstra(int n,int m,int c[75000001],int d[75000001],int l[75000001],int siten,bool mukou){ vector

e[514514]; rep(0,i,m){ e[c[i]].pb(P{l[i],d[i]}); if(mukou)e[d[i]].pb(P{l[i],c[i]}); } rep(0,i,n)dijkstraa[i]=inf; dijkstraa[siten]=0; priority_queue,greater

>pp; pp.push(P{0,siten}); while(!pp.empty()){ P t=pp.top();pp.pop(); if(t.first!=dijkstraa[t.second])continue; rep(0,i,e[t.s].size()){ P g=e[t.s][i]; if(dijkstraa[g.second]>t.first+g.first){ dijkstraa[g.second]=t.first+g.first; pp.push(P{dijkstraa[g.second],g.second}); } } } } int dijkstra2(int shuten){ return dijkstraa[shuten]; } vector toposo(vector> G,vector indegree,int n){ vector sorted_vertices; queue que; rep(0,i,n)if(!indegree[i])que.push(i); while(!que.empty()){ int v=que.front(); que.pop(); rep(0,i,G[v].size()){ int u=G[v][i]; indegree[u]-=1; if(!indegree[u])que.push(u); } sorted_vertices.pb(v); } return sorted_vertices; } struct segtree{ vector dat; int n; segtree(int n_):n(),dat(n_*4,inf){ int x=1; while(n_>=x)x*=2; n=x; } void update(int i,int x){ i+=n-1; dat[i]=x; while(i>0){ i=(i-1)/2; dat[i]=min(dat[i*2+1],dat[i*2+2]); } } int query(int a,int b){return query_sub(a,b,0,0,n);} int query_sub(int a,int b,int k,int l,int r){ if(r<=a||b<=l)return inf; else if(a<=l&&r<=b)return dat[k]; else{ int vl=query_sub(a,b,k*2+1,l,(l+r)/2); int vr=query_sub(a,b,k*2+2,(l+r)/2,r); return min(vl,vr); } } int rightest(int a,int b,int x){return rightest_sub(a,b,x,0,0,n);} int rightest_sub(int a,int b,int x,int k,int l,int r){ if(dat[k]>x||r<=a||b<=l)return a-1; else if(k>=n-1)return k-(n-1); else{ int vr=rightest_sub(a,b,x,2*k+2,(l+r)/2,r); if(vr!=a-1)return vr; else return rightest_sub(a,b,x,2*k+1,l,(l+r)/2); } } int leftest(int a,int b,int x){return leftest_sub(a,b,x,0,0,n);} int leftest_sub(int a,int b,int x,int k,int l,int r){ if(dat[k]>x||r<=a||b<=l)return b; else if(k>=n-1)return k-(n-1); else{ int vl=leftest_sub(a,b,x,2*k+1,l,(l+r)/2); if(vl!=b)return vl; else return leftest_sub(a,b,x,2*k+2,(l+r)/2,r); } } }; ll depth[100100],subtreesize[100100]; ll a[100100],b[100100]; vector edge[100100],v[100100]; void dfs(ll r,ll p,ll d){ depth[r]=d; rep(0,i,edge[r].size())if(edge[r][i]!=p)dfs(edge[r][i],r,d+1); rep(0,i,edge[r].size())if(edge[r][i]!=p)subtreesize[r]+=subtreesize[edge[r][i]]; subtreesize[r]++; } signed main(){ ic(n) rep(0,i,n-1){ cin>>a[i]>>b[i]; a[i]-=1,b[i]-=1; edge[a[i]].pb(b[i]); edge[b[i]].pb(a[i]); } dfs(0,-1,0); rep(0,i,n-1){ if(depth[a[i]]>depth[b[i]]){ v[a[i]].pb(n-subtreesize[a[i]]); v[b[i]].pb(subtreesize[a[i]]); } else{ v[b[i]].pb(n-subtreesize[b[i]]); v[a[i]].pb(subtreesize[b[i]]); } } int ans=0; rep(0,i,n){ rep(0,j,v[i].size()){ ans+=v[i][j]*(n-v[i][j]); } } ans=(n-1)*n*(n-1)-ans; ans%=mod; c(inv(ans,(n-1)*n*(n-1)%mod)) }