#include <algorithm>
#include <array>
#include <cassert>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <vector>

using namespace std;

void solve() {
  int n, k;
  cin >> n >> k;
  vector<int> v(n);
  for(auto& x: v) cin >> x;
  vector<vector<int>> edges(n);
  for(int i = 0; i < n; i++) {
    int a, b;
    cin >> a >> b;
    a--; b--;
    edges[a].push_back(b);
    edges[b].push_back(a);
  }
  vector<int> id(n, -1);
  int numtrees = 0;
  {  
    vector<int> st;
    vector<int> dp(n);
    bool done = false;
    auto dfs = [&](auto&& dfs, int curr, int par) -> void {
      if(done) return;
      if(dp[curr] == 1) {
        int nv = 0;
        for(int i = st.size()-1; i >= 0; i--) {
          id[st[i]] = nv++;
          if(st[i] == curr) break;
        }
        numtrees = nv;
        done = true;
        return;
      }
      dp[curr] = 1;
      st.push_back(curr);
      for(int out: edges[curr]) {
        if(out == par) continue;
        dfs(dfs, out, curr);
      }
      st.pop_back();
      dp[curr] = 2;
    };
    dfs(dfs, 0, -1);
    assert(done);
  }
  {
    queue<int> q;
    for(int i = 0; i < n; i++) {
      if(id[i] >= 0) q.push(i);
    }
    while(q.size()) {
      int curr = q.front(); q.pop();
      for(int out: edges[curr]) if(id[out] == -1) {
        q.push(out);
        id[out] = id[curr];
      }
    }
  }
  map<int, int> freq;
  vector<map<int, int>> treefreq(numtrees);
  for(int i = 0; i < n; i++) {
    freq[v[i]]++;
    treefreq[id[i]][v[i]]++;
  }
  int64_t ret = 0;
  for(int i = 0; i < n; i++) {
    ret += 2 * freq[v[i] + k];
    ret -= treefreq[id[i]][v[i] + k];
  }
  cout << ret << "\n";
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  solve();
}