#pragma GCC optimize("O3")
#pragma GCC optimize ("unroll-loops")
// #pragma GCC target("avx2")
#include <bits/stdc++.h>
#define ll long long
#define ull unsigned ll
#define ld long double
#define all(v, l) v.begin() + l, v.end()
#define rall(v, l) v.rbegin(), v.rend() - l
#define pb push_back
#define pf push_front
#define rsz resize
#define fi first
#define se second
#define LMAX LLONG_MAX
#define LMIN LLONG_MIN
#define IMAX INT_MAX
#define IMIN INT_MIN
#define endl "\n"
#define newline cout << endl;
using namespace std;
// structs
// structs
struct graph
{
vector <vector <int> > g;
vector <ll> lvl;
void prep(int n)
{
g.rsz(n);
lvl.rsz(n);
}
int limit, cnt;
void DFS(int v, int par)
{
for (auto u : g[v])
{
if (par == u)
{
continue;
}
DFS(u, v);
}
ll temp = lvl[v];
for (auto u : g[v])
{
if (par == u)
{
continue;
}
temp += lvl[u];
}
if (par != -1 && temp > limit)
{
cnt++;
}
else
{
lvl[v] = temp;
}
}
void cleanse()
{
cnt = 0;
}
};
// globals
// variables
int n, k;
// iterators
int i;
// notes
/*
-stuff you should look for-
* int overflow, array bounds
* special cases (n=1?)
* do something instead of nothing and stay organized
* WRITE STUFF DOWN
* DON'T GET STUCK ON ONE APPROACH
continue - skip the rest in the loop
*/
// functions
ll GCD(ll numeroune, ll numerodeux);
ll LCM(ll numeroune, ll numerodeux);
ll power(ll numeroune, ll numerodeux);
void solve()
{
graph G;
cin >> n >> k;
G.prep(n + 1);
for (i = 1; i <= n; i++)
{
cin >> G.lvl[i];
}
for (i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
G.g[u].pb(v);
G.g[v].pb(u);
}
G.cleanse();
G.limit = k;
G.DFS(1, -1);
cout << G.cnt;
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
while (t--)
{
solve();
newline
}
}
ll GCD(ll numeroune, ll numerodeux)
{
if (!numeroune)
{
return numerodeux;
}
return GCD(numerodeux % numeroune, numeroune);
}
ll LCM(ll numeroune, ll numerodeux)
{
return numeroune * numerodeux / GCD(numeroune, numerodeux);
}
ll power(ll numeroune, ll numerodeux)
{
ll res = 1;
while (numerodeux)
{
if (numerodeux & 1)
{
res *= numeroune;
}
numeroune *= numeroune;
numerodeux >>= 1;
}
return res;
}
/*
$$$$$$$$\ $$$$$$$$\
$$ _____|\____$$ |
$$ | $$ /
$$$$$\ $$ /
$$ __| $$ /
$$ | $$ /
$$$$$$$$\ $$$$$$$$\
\________|\________|
*/
