树分治，每次把每个点的deep取出，排序。。。尺取法。。。
# include <stdio.h>
# include <stdlib.h>
# include <iostream>
# include <algorithm>
# include <string.h>
# define IL inline
# define RG register
# define Fill(a, b) memset(a, b, sizeof(a))
using namespace std;
typedef long long ll;
IL ll Read(){
RG char c = getchar(); RG ll x = 0, z = 1;
for(; c < '0' || c > '9'; c = getchar()) z = c == '-' ? -1 : 1;
for(; c >= '0' && c <= '9'; c = getchar()) x = (x << 1) + (x << 3) + c - '0';
return x * z;
}
const int MAXN(20010), INF(2147483647);
int n, cnt, fst[MAXN], to[MAXN], nxt[MAXN], w[MAXN], k;
int size[MAXN], rt, sz, mx[MAXN], vis[MAXN];
ll ans, d[MAXN];
IL void Add(RG int u, RG int v, RG int f){ nxt[cnt] = fst[u]; to[cnt] = v; w[cnt] = f; fst[u] = cnt++; }
IL void Getroot(RG int u, RG int fa){
size[u] = 1; mx[u] = 0;
for(RG int e = fst[u]; e != -1; e = nxt[e]){
if(vis[to[e]] || to[e] == fa) continue;
Getroot(to[e], u);
size[u] += size[to[e]];
mx[u] = max(mx[u], size[to[e]]);
}
mx[u] = max(mx[u], sz - size[u]);
if(mx[u] < mx[rt]) rt = u;
}
IL void Getdeep(RG int u, RG int fa, RG ll dis){
d[++cnt] = dis;
for(RG int e = fst[u]; e != -1; e = nxt[e]){
if(vis[to[e]] || to[e] == fa) continue;
Getdeep(to[e], u, dis + w[e]);
}
}
IL ll Calc(RG int u, RG int f){
cnt = 0; Getdeep(u, 0, f);
sort(d + 1, d + cnt + 1);
RG ll ret = 0, l = 1, r = cnt;
while(l < r) if(d[r] + d[l] <= k) ret += r - l, l++; else r--;
return ret;
}
IL void Solve(RG int u){
ans += Calc(u, 0); vis[u] = 1;
for(RG int e = fst[u]; e != -1; e = nxt[e]){
if(vis[to[e]]) continue;
ans -= Calc(to[e], w[e]);
rt = 0; sz = size[to[e]];
Getroot(to[e], u);
Solve(rt);
}
}
int main(RG int argc, RG char* argv[]){
n = Read(); k = Read(); mx[0] = INF;
while(n && k){
Fill(fst, -1); Fill(vis, 0); rt = ans = cnt = 0; sz = n;
for(RG int i = 1, u, v, f; i < n; i++) u = Read(), v = Read(), f = Read(), Add(u, v, f), Add(v, u, f);
Getroot(1, 0); Solve(rt);
printf("%lld
", ans);
n = Read(); k = Read();
}
return 0;
}