#include <bits/stdc++.h> using namespace std; #define int long long const int sz = 1e5+5; int n, k; vector<vector<array<int,2>>> g(sz); vector<vector<int>> depthv(sz); int w[sz], depth[sz]; bool used[sz]; signed main() { ios_base::sync_with_stdio(0); cout.tie(0); cin >> n >> k; for(int i = 1;i <= n;i++) cin >> w[i]; for(int i = 1;i < n;i++) { int a, b; cin >> a >> b; g[a].push_back({w[b], b}); g[b].push_back({w[a], a}); } queue<array<int,2>> q; q.push({1, 0}); used[1] = 1; int bt = 0; while(!q.empty()) { int u = q.front()[0]; int d = q.front()[1]; q.pop(); bt = max(bt, d); depth[u] = d; depthv[d].push_back(u); for(auto &[we, to] : g[u]) { if(used[to]) continue; used[to] = 1; q.push({to, d+1}); } } bt--; int comp_cnt = n; for(;bt >= 0;bt--) { for(auto &u : depthv[bt]) { for(auto &[we, to] : g[u]) we = w[to]; sort(g[u].begin(), g[u].end()); for(auto &[we, to] : g[u]) { if(depth[to] != bt+1) continue; if(w[u] + we <= k) { w[u] += we; comp_cnt--; } } } } cout << comp_cnt - 1 << "\n"; }