// ~~ icebear love attttt ~~
#include <bits/stdc++.h>
using namespace std;
#define int ll
typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
template<class T>
bool minimize(T &a, const T &b) {
if (a > b) return a = b, true;
return false;
}
template<class T>
bool maximize(T &a, const T &b) {
if (a < b) return a = b, true;
return false;
}
#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "icebearat"
const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 2e5 + 5;
int n, k;
vector<ii> G[N];
int ft[N], sz[N];
bool isCentroid[N];
ll ans = 0;
vector<ii> global_nodes, internal_nodes;
void update(int x, int val) {
x++;
for(; x < N; x += x & -x) ft[x] += val;
}
int query(int x) {
x++;
int res = 0;
for(; x; x -= x & -x) res += ft[x];
return res;
}
void dfs(int u, int par) {
sz[u] = 1;
for(ii v : G[u]) if (v.fi != par && !isCentroid[v.fi]) {
dfs(v.fi, u);
sz[u] += sz[v.fi];
}
}
int findCentroid(int u, int par, const int &subtreeSize) {
for(ii v : G[u]) if (v.fi != par && !isCentroid[v.fi] && sz[v.fi] > subtreeSize / 2)
return findCentroid(v.fi, u, subtreeSize);
return u;
}
void solve(vector<ii> &nodes, int sign) {
ll sum = 0;
sort(all(nodes));
for(ii p : nodes) {
if (p.fi - p.se >= 0) sum += query(p.fi - p.se);
update(p.se, +1);
}
for(ii p : nodes) update(p.se, -1);
ans += sum * sign;
}
void add_node(int u, int par, int maxW, int depth) {
global_nodes.emplace_back(maxW, depth);
internal_nodes.emplace_back(maxW, depth);
for(ii v : G[u]) if (v.fi != par && !isCentroid[v.fi])
add_node(v.fi, u, max(maxW, v.se), depth + 1);
}
void buildCentroid(int u) {
dfs(u, -1);
int centroid = findCentroid(u, -1, sz[u]);
global_nodes.emplace_back(0, 0);
for(ii v : G[centroid]) if (!isCentroid[v.fi]) {
add_node(v.fi, centroid, v.se, 1);
solve(internal_nodes, -1);
internal_nodes.clear();
}
solve(global_nodes, +1);
global_nodes.clear();
isCentroid[centroid] = true;
for(ii v : G[centroid]) if (!isCentroid[v.fi])
buildCentroid(v.fi);
}
void init(void) {
cin >> n >> k;
FOR(i, 2, n) {
int u, v, w;
cin >> u >> v >> w;
w -= k;
G[u].pb(mp(v, w));
G[v].pb(mp(u, w));
}
}
void process(void) {
buildCentroid(1);
cout << ans * 2;
}
signed main() {
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
if (fopen(task".inp", "r")) {
freopen(task".inp", "r", stdin);
freopen(task".out", "w", stdout);
}
int tc = 1;
// cin >> tc;
while(tc--) {
init();
process();
}
return 0;
}
