#include "bits/stdc++.h" using namespace std; typedef long long ll; typedef pair<ll, ll> pii; #define all(x) x.begin(), x.end() #define sz(x) ((int) ((x).size())) #define pb push_back #define F first #define S second #define FIO ios_base::sync_with_stdio(false); cin.tie(0) const int N = 2e5 + 10; int n, k; int a[N]; int par[N]; vector<int> adj[N]; int ans; int dfs(int node) { multiset<int> s; for (int x : adj[node]) { if (par[node] == x) continue; par[x] = node; s.insert(dfs(x)); } int cur = a[node]; while (sz(s) and cur + *s.begin() <= k) { cur += *s.begin(); s.erase(s.begin()); } ans += sz(s); return cur; } int main() { FIO; cin >> n >> k; for (int i = 1; i <= n; i++) { cin >> a[i]; } for (int i = 0; i < n - 1; i++) { int x, y; cin >> x >> y; adj[x].pb(y); adj[y].pb(x); } dfs(1); cout << ans << endl; return 0; }