import bisect import copy import decimal import fractions import heapq import itertools import math import random import sys import time from collections import Counter, deque,defaultdict from functools import lru_cache,reduce from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max def _heappush_max(heap,item): heap.append(item) heapq._siftdown_max(heap, 0, len(heap)-1) def _heappushpop_max(heap, item): if heap and item < heap[0]: item, heap[0] = heap[0], item heapq._siftup_max(heap, 0) return item from math import gcd as Gcd read=sys.stdin.read readline=sys.stdin.readline readlines=sys.stdin.readlines class Graph: def __init__(self,V,edges=False,graph=False,directed=False,weighted=False): self.V=V self.directed=directed self.weighted=weighted if not graph: self.edges=edges self.graph=[[] for i in range(self.V)] if weighted: for i,j,d in self.edges: self.graph[i].append((j,d)) if not self.directed: self.graph[j].append((i,d)) else: for i,j in self.edges: self.graph[i].append(j) if not self.directed: self.graph[j].append(i) else: self.graph=graph self.edges=[] for i in range(self.V): if self.weighted: for j,d in self.graph[i]: if self.directed or not self.directed and i<=j: self.edges.append((i,j,d)) else: for j in self.graph[i]: if self.directed or not self.directed and i<=j: self.edges.append((i,j)) def SIV_BFS(self,s,bfs_tour=False,bipartite_graph=False,linked_components=False,parents=False,unweighted_dist=False,weighted_dist=False): seen=[False]*self.V seen[s]=True if bfs_tour: bt=[s] if linked_components: lc=[s] if parents: ps=[None]*self.V if unweighted_dist or bipartite_graph: uwd=[float('inf')]*self.V uwd[s]=0 if weighted_dist: wd=[float('inf')]*self.V wd[s]=0 queue=deque([s]) while queue: x=queue.popleft() for y in self.graph[x]: if self.weighted: y,d=y if not seen[y]: seen[y]=True queue.append(y) if bfs_tour: bt.append(y) if linked_components: lc.append(y) if parents: ps[y]=x if unweighted_dist or bipartite_graph: uwd[y]=uwd[x]+1 if weighted_dist: wd[y]=wd[x]+d if bipartite_graph: bg=[[],[]] for tpl in self.edges: i,j=tpl[:2] if self.weighted else tpl if type(uwd[i])==float or type(uwd[j])==float: continue if not uwd[i]%2^uwd[j]%2: bg=False break else: for x in range(self.V): if type(uwd[x])==float: continue bg[uwd[x]%2].append(x) retu=() if bfs_tour: retu+=(bt,) if bipartite_graph: retu+=(bg,) if linked_components: retu+=(lc,) if parents: retu+=(ps,) if unweighted_dist: retu+=(uwd,) if weighted_dist: retu+=(wd,) if len(retu)==1: retu=retu[0] return retu def MIV_BFS(self,initial_vertices=False,bipartite_graph=False,linked_components=False,parents=False): if not initial_vertices: initial_vertices=[i for i in range(self.V)] seen=[False]*self.V if bipartite_graph: bg=[None]*self.V cnt=-1 if linked_components: lc=[] if parents: ps=[None]*self.V for s in initial_vertices: if seen[s]: continue seen[s]=True if bipartite_graph: cnt+=1 bg[s]=(cnt,0) if linked_components: lc.append([s]) queue=deque([s]) while queue: x=queue.popleft() for y in self.graph[x]: if self.weighted: y,d=y if not seen[y]: seen[y]=True queue.append(y) if bipartite_graph: bg[y]=(cnt,bg[x][1]^1) if linked_components: lc[-1].append(y) if parents: ps[y]=x if bipartite_graph: bg_=bg bg=[[[],[]] for i in range(cnt+1)] for tpl in self.edges: i,j=tpl[:2] if self.weighted else tpl if not bg_[i][1]^bg_[j][1]: bg[bg_[i][0]]=False for x in range(self.V): if bg[bg_[x][0]]: bg[bg_[x][0]][bg_[x][1]].append(x) retu=() if bipartite_graph: retu+=(bg,) if linked_components: retu+=(lc,) if parents: retu=(ps,) if len(retu)==1: retu=retu[0] return retu def SIV_DFS(self,s,bipartite_graph=False,cycle_detection=False,directed_acyclic=False,euler_tour=False,linked_components=False,parents=False,postorder=False,preorder=False,subtree_size=False,topological_sort=False,unweighted_dist=False,weighted_dist=False): seen=[False]*self.V finished=[False]*self.V if directed_acyclic or cycle_detection or topological_sort: dag=True if euler_tour: et=[] if linked_components: lc=[] if parents or cycle_detection or subtree_size: ps=[None]*self.V if postorder or topological_sort: post=[] if preorder: pre=[] if subtree_size: ss=[1]*self.V if unweighted_dist or bipartite_graph: uwd=[float('inf')]*self.V uwd[s]=0 if weighted_dist: wd=[float('inf')]*self.V wd[s]=0 stack=[(s,0)] if self.weighted else [s] while stack: if self.weighted: x,d=stack.pop() else: x=stack.pop() if not seen[x]: seen[x]=True stack.append((x,d) if self.weighted else x) if euler_tour: et.append(x) if linked_components: lc.append(x) if preorder: pre.append(x) for y in self.graph[x]: if self.weighted: y,d=y if not seen[y]: stack.append((y,d) if self.weighted else y) if parents or cycle_detection or subtree_size: ps[y]=x if unweighted_dist or bipartite_graph: uwd[y]=uwd[x]+1 if weighted_dist: wd[y]=wd[x]+d elif not finished[y]: if (directed_acyclic or cycle_detection or topological_sort) and dag: dag=False if cycle_detection: cd=(y,x) elif not finished[x]: finished[x]=True if euler_tour: et.append(~x) if postorder or topological_sort: post.append(x) if subtree_size: for y in self.graph[x]: if self.weighted: y,d=y if y==ps[x]: continue ss[x]+=ss[y] if bipartite_graph: bg=[[],[]] for tpl in self.edges: i,j=tpl[:2] if self.weighted else tpl if type(uwd[i])==float or type(uwd[j])==float: continue if not uwd[i]%2^uwd[j]%2: bg=False break else: for x in range(self.V): if type(uwd[x])==float: continue bg[uwd[x]%2].append(x) retu=() if bipartite_graph: retu+=(bg,) if cycle_detection: if dag: cd=[] else: y,x=cd cd=self.Route_Restoration(y,x,ps) retu+=(cd,) if directed_acyclic: retu+=(dag,) if euler_tour: retu+=(et,) if linked_components: retu+=(lc,) if parents: retu+=(ps,) if postorder: retu+=(post,) if preorder: retu+=(pre,) if subtree_size: retu+=(ss,) if topological_sort: if dag: tp_sort=post[::-1] else: tp_sort=[] retu+=(tp_sort,) if unweighted_dist: retu+=(uwd,) if weighted_dist: retu+=(wd,) if len(retu)==1: retu=retu[0] return retu def MIV_DFS(self,initial_vertices=False,bipartite_graph=False,cycle_detection=False,directed_acyclic=False,euler_tour=False,linked_components=False,parents=False,postorder=False,preorder=False,subtree_size=False,topological_sort=False,unweighted_dist=False,weighted_dist=False): if not initial_vertices: initial_vertices=[s for s in range(self.V)] seen=[False]*self.V finished=[False]*self.V if bipartite_graph: bg=[None]*self.V cnt=-1 if directed_acyclic or cycle_detection or topological_sort: dag=True if euler_tour: et=[] if linked_components: lc=[] if parents or cycle_detection or subtree_size: ps=[None]*self.V if postorder or topological_sort: post=[] if preorder: pre=[] if subtree_size: ss=[1]*self.V if unweighted_dist: uwd=[float('inf')]*self.V if weighted_dist: wd=[float('inf')]*self.V for s in initial_vertices: if seen[s]: continue if bipartite_graph: cnt+=1 bg[s]=(cnt,0) if linked_components: lc.append([]) if unweighted_dist: uwd[s]=0 if weighted_dist: wd[s]=0 stack=[(s,0)] if self.weighted else [s] while stack: if self.weighted: x,d=stack.pop() else: x=stack.pop() if not seen[x]: seen[x]=True stack.append((x,d) if self.weighted else x) if euler_tour: et.append(x) if linked_components: lc[-1].append(x) if preorder: pre.append(x) for y in self.graph[x]: if self.weighted: y,d=y if not seen[y]: stack.append((y,d) if self.weighted else y) if bipartite_graph: bg[y]=(cnt,bg[x][1]^1) if parents or cycle_detection or subtree_size: ps[y]=x if unweighted_dist or bipartite_graph: uwd[y]=uwd[x]+1 if weighted_dist: wd[y]=wd[x]+d elif not finished[y]: if directed_acyclic and dag: dag=False if cycle_detection: cd=(y,x) elif not finished[x]: finished[x]=True if euler_tour: et.append(~x) if postorder or topological_sort: post.append(x) if subtree_size: for y in self.graph[x]: if self.weighted: y,d=y if y==ps[x]: continue ss[x]+=ss[y] if bipartite_graph: bg_=bg bg=[[[],[]] for i in range(cnt+1)] for tpl in self.edges: i,j=tpl[:2] if self.weighted else tpl if not bg_[i][1]^bg_[j][1]: bg[bg_[i][0]]=False for x in range(self.V): if bg[bg_[x][0]]: bg[bg_[x][0]][bg_[x][1]].append(x) retu=() if bipartite_graph: retu+=(bg,) if cycle_detection: if dag: cd=[] else: y,x=cd cd=self.Route_Restoration(y,x,ps) retu+=(cd,) if directed_acyclic: retu+=(dag,) if euler_tour: retu+=(et,) if linked_components: retu+=(lc,) if parents: retu+=(ps,) if postorder: retu+=(post,) if preorder: retu+=(pre,) if subtree_size: retu+=(ss,) if topological_sort: if dag: tp_sort=post[::-1] else: tp_sort=[] retu+=(tp_sort,) if unweighted_dist: retu+=(uwd,) if weighted_dist: retu+=(wd,) if len(retu)==1: retu=retu[0] return retu def Tree_Diameter(self,weighted=False): def Farthest_Point(u): dist=self.SIV_BFS(u,weighted_dist=True) if weighted else self.SIV_BFS(u,unweighted_dist=True) fp=0 for i in range(self.V): if dist[fp]=0: self.lca_dfs_in_index[x]=i else: self.lca_dfs_out_index[~x]=i self.ST=Segment_Tree(2*self.V,lambda x,y:min(x,y),self.V) lst=[None]*(2*self.V) for i in range(2*self.V-1): if self.lca_euler_tour[i]>=0: lst[i]=depth[self.lca_euler_tour[i]] else: lst[i]=depth[self.lca_parents[~self.lca_euler_tour[i]]] lst[2*self.V-1]=-1 self.ST.Build(lst) def LCA(self,a,b): m=min(self.lca_dfs_in_index[a],self.lca_dfs_in_index[b]) M=max(self.lca_dfs_in_index[a],self.lca_dfs_in_index[b]) x=self.lca_euler_tour[self.ST.Fold_Index(m,M+1)] if x>=0: return x else: return self.lca_parents[~x] def Build_HLD(self,s): self.hld_parents,size,self.hld_depth=self.SIV_DFS(s,parents=True,subtree_size=True,unweighted_dist=True) stack=[s] self.hld_tour=[] self.hld_path_parents=[None]*self.V self.hld_path_parents[s]=s while stack: x=stack.pop() self.hld_tour.append(x) max_size=0 max_size_y=None for y in self.graph[x]: if self.weighted: y,d=y if y==self.hld_parents[x]: continue if max_sizesize[root]: x=y break else: for y in self.graph[x]: if y==parents[x]: continue if size[root]<=2*size[y]: return x,y return x,None def Centroid_Decomposition(self,edge=False,linked_point=False,point=False,tree=False): if edge: cd_edges_lst=[None]*self.V if linked_point: cd_linked_points=[None]*self.V if point: cd_points_lst=[None]*self.V if tree: cd_tree=[]*self.V if self.weighted: edges=[(i,j) for i,j,d in self.edges] else: edges=self.edges points=[i for i in range(self.V)] prev_centroid=None stack=[(edges,points,None,prev_centroid)] if linked_point else [(edges,points,prev_centroid)] while stack: if linked_point: edges,points,lp,prev_centroid=stack.pop() else: edges,points,prev_centroid=stack.pop() if len(points)==1: centroid=points[0] if edge: cd_edges_lst[centroid]=[] if linked_point: cd_linked_points[centroid]=lp if point: cd_points_lst[centroid]=[centroid] if tree and prev_centroid!=None: cd_tree.append((prev_centroid,centroid)) continue G=Graph(len(points),edges=edges) centroid,_=G.Centroid() if tree and prev_centroid!=None: cd_tree.append((prev_centroid,points[centroid])) parents,tour=G.SIV_DFS(centroid,parents=True,preorder=True) dp=[None]*len(points) edges_lst=[] points_lst=[] if linked_point: linked_points=[] for i,x in enumerate(G.graph[centroid]): dp[x]=(i,0) edges_lst.append([]) points_lst.append([points[x]]) if linked_point: linked_points.append(points[x]) for x in tour[1:]: for y in G.graph[x]: if y==parents[x]: continue i,j=dp[x] jj=len(points_lst[i]) edges_lst[i].append((j,jj)) points_lst[i].append(points[y]) dp[y]=(i,jj) centroid=points[centroid] if edge: cd_edges_lst[centroid]=edges if linked_point: cd_linked_points[centroid]=lp if point: cd_points_lst[centroid]=points if linked_point: for edges,points,lp in zip(edges_lst,points_lst,linked_points): stack.append((edges,points,lp,centroid)) else: for edges,points in zip(edges_lst,points_lst): stack.append((edges,points,centroid)) retu=() if edge: retu+=(cd_edges_lst,) if linked_point: retu+=(cd_linked_points,) if point: retu+=(cd_points_lst,) if tree: retu+=(cd_tree,) if len(retu)==1: retu=retu[0] return retu def Dijkstra(self,s,route_restoration=False): dist=[float('inf')]*self.V dist[s]=0 hq=[(0,s)] if route_restoration: parents=[None]*self.V while hq: dx,x=heapq.heappop(hq) if dist[x]dx+dy: dist[y]=dx+dy if route_restoration: parents[y]=x heapq.heappush(hq,(dist[y],y)) if route_restoration: return dist,parents else: return dist def Bellman_Ford(self,s,route_restoration=False): dist=[float('inf')]*self.V dist[s]=0 if route_restoration: parents=[None]*self.V for _ in range(self.V-1): for i,j,d in self.edges: if dist[j]>dist[i]+d: dist[j]=dist[i]+d if route_restoration: parents[j]=i if not self.directed and dist[i]>dist[j]+d: dist[i]=dist[j]+d if route_restoration: parents[i]=j negative_cycle=[] for i,j,d in self.edges: if dist[j]>dist[i]+d: negative_cycle.append(j) if not self.directed and dist[i]>dist[j]+d: negative_cycle.append(i) if negative_cycle: is_negative_cycle=[False]*self.V for i in negative_cycle: if is_negative_cycle[i]: continue else: queue=deque([i]) is_negative_cycle[i]=True while queue: x=queue.popleft() for y,d in self.graph[x]: if not is_negative_cycle[y]: queue.append(y) is_negative_cycle[y]=True if route_restoration: parents[y]=x for i in range(self.V): if is_negative_cycle[i]: dist[i]=-float('inf') if route_restoration: return dist,parents else: return dist def Warshall_Floyd(self,route_restoration=False): dist=[[float('inf')]*self.V for i in range(self.V)] for i in range(self.V): dist[i][i]=0 if route_restoration: parents=[[j for j in range(self.V)] for i in range(self.V)] for i,j,d in self.edges: if i==j: continue if dist[i][j]>d: dist[i][j]=d if route_restoration: parents[i][j]=i if not self.directed and dist[j][i]>d: dist[j][i]=d if route_restoration: parents[j][i]=j for k in range(self.V): for i in range(self.V): for j in range(self.V): if dist[i][j]>dist[i][k]+dist[k][j]: dist[i][j]=dist[i][k]+dist[k][j] if route_restoration: parents[i][j]=parents[k][j] for i in range(self.V): if dist[i][i]<0: for j in range(self.V): if dist[i][j]!=float('inf'): dist[i][j]=-float('inf') if route_restoration: for i in range(self.V): if dist[i][i]==0: parents[i][i]=None return dist,parents else: return dist def Route_Restoration(self,s,g,parents): route=[g] while s!=g: if parents[g]==None: route=[] break g=parents[g] route.append(g) route=route[::-1] return route def Kruskal(self): UF=UnionFind(self.V) sorted_edges=sorted(self.edges,key=lambda x:x[2]) minimum_spnning_tree=[] for i,j,d in sorted_edges: if not UF.Same(i,j): UF.Union(i,j) minimum_spnning_tree.append((i,j,d)) return minimum_spnning_tree def Ford_Fulkerson(self,s,t): max_flow=0 residual_graph=[defaultdict(int) for i in range(self.V)] if self.weighted: for i,j,d in self.edges: if not d: continue residual_graph[i][j]+=d if not self.directed: residual_graph[j][i]+=d else: for i,j in self.edges: residual_graph[i][j]+=1 if not self.directed: residual_graph[j][i]+=1 while True: parents=[None]*self.V parents[s]=s seen=[False]*self.V seen[s]=True queue=deque([s]) while queue: x=queue.popleft() for y in residual_graph[x].keys(): if not seen[y]: seen[y]=True queue.append(y) parents[y]=x if y==t: tt=t while tt!=s: residual_graph[parents[tt]][tt]-=1 residual_graph[tt][parents[tt]]+=1 if not residual_graph[parents[tt]][tt]: residual_graph[parents[tt]].pop(tt) tt=parents[tt] max_flow+=1 break else: continue break else: break return max_flow def BFS(self,s): seen=[False]*self.V seen[s]=True queue=deque([s]) while queue: x=queue.popleft() for y in self.graph[x]: if self.weighted: y,d=y if not seen[y]: seen[y]=True queue.append(y) return def DFS(self,s): seen=[False]*self.V finished=[False]*self.V stack=[(s,0)] if self.weighted else [s] while stack: if self.weighted: x,d=stack.pop() else: x=stack.pop() if not seen[x]: seen[x]=True stack.append((x,d) if self.weighted else x) for y in self.graph[x]: if self.weighted: y,d=y if not seen[y]: stack.append((y,d) if self.weighted else y) elif not finished[x]: finished[x]=True return N,K=map(int,readline().split()) color={} edges=[] for _ in range(N-1): u,v,c=map(int,readline().split()) u-=1;v-=1 color[(u,v)]=c color[(v,u)]=c edges.append((u,v)) G=Graph(N,edges=edges) cd_edges,cd_linked_points,cd_points,cd_tree=G.Centroid_Decomposition(edge=True,linked_point=True,point=True,tree=True) CD=Graph(N,edges=cd_tree) cd_parents,cd_tour=CD.SIV_DFS(cd_tree[0][0],parents=True,postorder=True) dp=[0]*N for x in cd_tour: dct_lst=[] cnt1=defaultdict(int) cnt2=defaultdict(int) for y in CD.graph[x]: if y==cd_parents[x]: continue dp[x]+=dp[y] G_y=Graph(len(cd_points[y]),edges=cd_edges[y]) dp_color=[None]*len(cd_points[y]) for s in range(len(cd_points[y])): if cd_points[s]==cd_linked_points[y]: break dp_color[s]=(color[(cd_linked_points[y],x)],None) parents,tour=G_y.SIV_DFS(s,parents=True,preorder=True) for xx in tour[1:]: a,b=dp_color[parents[xx]] c=color[(cd_points[y][xx],cd_points[y][parents[xx]])] if c in (a,b): dp_color[xx]=(a,b) elif b==None: dp_color[xx]=(a,c) C1,C2=defaultdict(int),defaultdict(int) for tpl in dp_color: if tpl==None: continue a,b=tpl if b==None: C1[a]+=1 else: C2[(a,b)]+=1 for (a,b),c in C2.items(): dp[x]-=c*(c-1)//2 dp[x]-=c*(C1[a]+C1[b]) for a,c in C1.items(): cnt1[a]+=c for tpl,c in C2.items(): cnt2[tpl]+=c for (a,b),c in cnt2.items(): dp[x]+=c dp[x]+=c*(c-1)//2 dp[x]+=c*(cnt1[a]+cnt1[b]) dp[x]+=(sum(cnt1.values())**2-sum(c**2 for c in cnt1.values()))//2 ans=dp[cd_tour[-1]] print(ans)