#include <bits/stdc++.h>
#define boAshraf ios_base::sync_with_stdio(false); cin.tie(NULL);
#define ll long long
#define sz(s) (int)(s).size()
#define all(s) (s).begin(),(s).end()
using namespace std;
void File();
void sol();

struct Node;
extern Node *emp;
struct Node {
    Node *left, *right;
    int val;
    Node() {
        left = right = this;
        val = 0;
    }
    Node(int val, Node *L = emp, Node *R = emp) : val(val), left(L), right(R) {}
};

Node *emp = new Node();
const int N = 2e4 + 5;
Node *seg[N] = {emp};
Node *insert(Node *root, int start, int end, int idx) {
    if (idx > end || idx < start) return root;
    if (start == end) {
        return new Node(root->val + 1);
    }
    int mid = start + end >> 1;
    Node *L = insert(root->left, start, mid, idx);
    Node *R = insert(root->right, mid + 1, end, idx);
    return new Node(L->val + R->val, L, R);
}

int query(Node* L, Node* R, int start, int end, int k) {
    if (end <= k) return R->val-L->val;
    if (start > k) return 0;
    int mid = start + end >> 1;
    return query(L->left, R->left, start, mid, k) + query(L->right, R->right, mid + 1, end, k);
}

int main() {
    boAshraf
    File();
    int t = 1;
//    cin >> t;
    while (t--) {
        sol();
    }
    return 0;
}

void sol() {
    int n,m;
    cin>>n>>m;
    vector<int>val(n+1),siz(n+1),d(n+1);
    for(int i=1;i<=n;i++)cin>>val[i];
    vector<vector<int>>adj(n+1);
    vector<int>topo;
    for(int i=1;i<n;i++){
        int u,v;
        cin>>u>>v;
        adj[u].emplace_back(v);
        adj[v].emplace_back(u);
    }
    auto dfs=[&](auto &self,int u,int p)->void{
        topo.emplace_back(u);
        seg[u]= insert(seg[p],0,1e9,val[u]);
        siz[u]=1;
        d[u]=d[p]+1;
        for(auto v:adj[u]){
            if(v==p)continue;
            self(self,v,u);
            siz[u]+=siz[v];
        }
    };
    dfs(dfs,1,0);
    vector<int>c(n+1,-1);
    auto calc=[&](int u,int val)->int{
        if(~c[u])return c[u];
        int idx=val/2+1;
        int l=0,r=1e9,ans=0;
        while(l<=r){
            int mid=(l+r)/2;
            if(query(seg[0],seg[u],0,1e9,mid)>=idx)ans=mid,r=mid-1;
            else l=mid+1;
        }
        return c[u]=ans;
    };
    vector<vector<ll>>dp(n+1,vector<ll>(m+1,-1));
    auto rec=[&](auto &self,int i,int rem)->ll{
        if(i==n || rem==0)return 0;
        ll &ret=dp[i][rem];
        if(~ret)return ret;
        int u=topo[i];
        ret=self(self,i+siz[u],rem);
        ret=max(ret,self(self,i+1,rem-1)+calc(u,d[u]));
        return ret;
    };
    cout<<rec(rec,0,m);
}

void File() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
}