#include using namespace std; using ll = long long; struct CentroidDecomposition_Old { vector> g, cd; vector used, ord; int n, r; CentroidDecomposition_Old(vector> &g_): g(g_) { n = g_.size(); used = vector(n); cd = vector>(n); dfs(0,-1,n,-1); } int dfs(int node, int p, int sz, int root){ if(used[node])return 0; bool b=true; int res=1; for(auto e:g[node]){ if(p==e)continue; int t = dfs(e,node,sz,root); if (t==-1) return -1; res+=t; if(t>sz/2)b=false; } if(!b||sz-res>sz/2)return res; if(root!=-1)cd[root].emplace_back(node); else r=node; ord.push_back(node); used[node]=1; for(auto e:g[node])dfs(e,node,dfs(e,node,n*2,node),node); return -1; } }; struct CentroidDecomposition { int n, r; vector> g, cd; vector ord, szs, used; CentroidDecomposition(vector> &gg): g(gg), n(gg.size()), used(n), cd(n), szs(n) { dfs1(0,-1); dfs(0,-1,n,-1); } int dfs1(int v, int p) { if(used[v]) return 0; szs[v]=1; for(auto e:g[v])if(e!=p)szs[v]+=dfs1(e,v); return szs[v]; } bool dfs(int node, int p, int sz, int root){ if(used[node] || sz-szs[node]>sz/2)return false; int res=1; for(auto e:g[node]){ if (p==e || szs[e]sync_with_stdio(false); int n, k; cin >> n >> k; using pii = pair; vector> g(n); vector> edges(n); for (int i = 0; i < n - 1; i++) { int u, v, c; cin >> u >> v >> c; u--, v--, c--; g[u].push_back(v); g[v].push_back(u); edges[u].emplace_back(v, c); edges[v].emplace_back(u, c); } CentroidDecomposition cd(g); // CentroidDecomposition_Old cd_old(g); // assert(cd_old.cd == cd.cd); vector visited(n); ll ans = 0; for (int ce : cd.ord) { int cnt0 = 0; // *, - int cnt1 = 0; // *, * map cnt2; // x, y map cnt3; // x, * map cnt4; // x, - auto f1 = [&](auto self, int node, int parent, int c1, int c2) -> void { if (c2 == -1) { cnt0++; cnt4[c1]++; } else { cnt1++; cnt2[make_pair(min(c1, c2), max(c1, c2))]++; cnt3[c1]++; cnt3[c2]++; } for (auto [child, c] : edges[node]) { if (child == parent || visited[child]) continue; if (c1 == c) { self(self, child, node, c1, c2); } else if (c2 == c || c2 == -1) { self(self, child, node, c1, c); } } }; auto f2 = [&](auto self, int node, int parent, int c1, int c2) -> void { if (c2 == -1) { ans += cnt0 - cnt4[c1] + cnt3[c1]; } else { ans += cnt2[make_pair(min(c1, c2), max(c1, c2))] + cnt4[c1] + cnt4[c2]; } for (auto [child, c] : edges[node]) { if (child == parent || visited[child]) continue; if (c1 == c) { self(self, child, node, c1, c2); } else if (c2 == c || c2 == -1) { self(self, child, node, c1, c); } } }; for (auto [child, c] : edges[ce]) { if (visited[child]) continue; f2(f2, child, ce, c, -1); f1(f1, child, ce, c, -1); } ans += cnt1; visited[ce] = true; } cout << ans << endl; }