#include <bits/stdc++.h>
#define ff first
#define ss second
using namespace std;
const int maxn = 2e5 + 10;
int n,k;
map<int,int> mp[maxn];
int id[maxn],d[maxn];
vector <pair<int,int>> adj[maxn];
int ans[maxn];
void dfs(int x, int p, int depth)
{
ans[x]=0;
mp[id[x]][depth]++;
for (int i=0; i<(int)adj[x].size(); i++)
{
int v = adj[x][i].ff; int w=adj[x][i].ss;
if (v==p) continue;
dfs(v,x,depth+w);
if (mp[id[i]].size()<mp[id[x]].size())
{
for (pair<int,int> j: mp[id[i]])
{
ans[x] += mp[id[x]][k - (j.ff - depth) +depth]*j.ss;
mp[id[x]][j.ff]+=j.ss;
}
}
else
{
for (pair<int,int> j: mp[id[x]])
{
ans[x] += mp[id[i]][k - (j.ff - depth) +depth]*j.ss;
mp[id[i]][j.ff]+=j.ss;
}
id[x]=id[i];
}
}
}
int best_path(int N, int K, int H[][2], int L[])
{
for (int i=1; i<=n; i++) id[i]=i;
for (int i=0; i<n-1; i++)
{
int u=H[i][0]; int v=H[i][1];
u++; v++;
adj[u].push_back({v,L[i]});
adj[v].push_back({u,L[i]});
}
dfs(1,1,0);
int res=0LL;
for (int i=1; i<=n; i++) res+=ans[i];
return res;
}
