#include <bits/stdc++.h>
#define fo(i, d, c) for (int i = d; i <= c; i++)
#define fod(i, c, d) for (int i = c; i >= d; i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout << "\n";
#define int long long
#define inf (int)1e18
#define pii pair<int, int>
#define vii vector<pii>
#define lb(x) x & -x
#define bit(i, j) ((i >> j) & 1)
#define offbit(i, j) (i ^ (1 << j))
#define onbit(i, j) (i | (1 << j))
#define vi vector<int>
template <typename T1, typename T2>
bool minimize(T1 &a, T2 b)
{
if (a > b)
{
a = b;
return true;
}
return false;
}
template <typename T1, typename T2>
bool maximize(T1 &a, T2 b)
{
if (a < b)
{
a = b;
return true;
}
return false;
}
using namespace std;
const int nsqrt = 450;
const int mod = 1e9 + 7;
struct BIT
{
int t[maxn];
void up(int x, int val)
{
x++;
for (; x; x -= lb(x))
t[x] += val;
}
int get(int x)
{
int ans = 0;
x++;
for (; x < maxn; x += lb(x))
ans += t[x];
return ans;
}
} t;
int n, k;
vii ke[maxn];
int ans;
// centroid decomposition
bool is_remove[maxn];
vii event;
int sz[maxn];
int d[maxn], val[maxn];
int dfs_size(int u, int parent = -1)
{
sz[u] = 1;
for (auto [v, w] : ke[u])
{
if (v == parent or is_remove[v])
continue;
sz[u] += dfs_size(v, u);
}
return sz[u];
}
int dfs_centroid(int u, int tree_size, int parent = 0)
{
for (auto [v, w] : ke[u])
{
if (v == parent or is_remove[v])
continue;
if (2 * sz[v] > tree_size)
return dfs_centroid(v, tree_size, u);
}
return u;
}
void dfs_dist(int u, int par, int dist, int maxx)
{
for (auto [v, w] : ke[u])
{
if (v == par or is_remove[v])
continue;
dfs_dist(v, u, dist + 1, max(maxx, w));
}
event.pb(maxx, dist);
d[u] = dist;
val[u] = maxx;
}
void solve(int val)
{
sort(event.begin(), event.end(), greater<pii>());
for (auto [maxx, dist] : event)
{
// cout << maxx << ' ' << dist << "\n";
ans += t.get(dist) * val;
if (maxx - dist - k >= 0)
t.up(maxx - dist - k, 1);
}
// cout << ans;en;
// cout << "xxxxxxxx\n";
for (auto [maxx, dist] : event)
{
if (maxx - dist - k >= 0)
t.up(maxx - dist - k, -1);
}
event.clear();
}
vi child;
void dfs_set(int u, int parent = -1)
{
child.pb(u);
for (auto [v, w] : ke[u])
{
if (v == parent or is_remove[v])
continue;
dfs_set(v, u);
}
}
void build_centroid(int u)
{
u = dfs_centroid(u, dfs_size(u));
is_remove[u] = 1;
// do sth
dfs_dist(u, u, 0, 0);
solve(1);
for (auto [v, w] : ke[u])
{
if (is_remove[v])
continue;
dfs_set(v);
for (int it : child)
event.pb(val[it], d[it]);
solve(-1);
child.clear();
}
for (auto [v, w] : ke[u])
{
if (is_remove[v])
continue;
build_centroid(v);
}
}
main()
{
#define name "TASK"
if (fopen(name ".inp", "r"))
{
freopen(name ".inp", "r", stdin);
freopen(name ".out", "w", stdout);
}
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cin >> n >> k;
fo(i, 1, n - 1)
{
int u, v, w;
cin >> u >> v >> w;
ke[u].pb(v, w);
ke[v].pb(u, w);
}
build_centroid(1);
cout << ans * 2;
}
