//#pragma GCC optimize(3)

//#pragma comment(linker, "/STACK:102400000,102400000")  //c++

// #pragma GCC diagnostic error "-std=c++11"

// #pragma comment(linker, "/stack:200000000")

// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#include <algorithm>

#include  <iterator>

#include  <iostream>

#include   <cstring>

#include   <cstdlib>

#include   <iomanip>

#include    <bitset>

#include    <cctype>

#include    <cstdio>

#include    <string>

#include    <vector>

#include     <stack>

#include     <cmath>

#include     <queue>

#include      <list>

#include       <map>

#include       <set>

#include   <cassert>

using namespace std;

#define lson (l , mid , rt << 1)

#define rson (mid + 1 , r , rt << 1 | 1)

#define debug(x) cerr << #x << " = " << x << "\n";

#define pb push_back

#define pq priority_queue

typedef long long ll;

typedef unsigned long long ull;

//typedef __int128 bll;

typedef pair<ll ,ll > pll;

typedef pair<int ,int > pii;

typedef pair<int,pii> p3;

//priority_queue<int> q;//这是一个大根堆q

//priority_queue<int,vector<int>,greater<int> >q;//这是一个小根堆q

#define fi first

#define se second

//#define endl '\n'

#define OKC ios::sync_with_stdio(false);cin.tie(0)

#define FT(A,B,C) for(int A=B;A <= C;++A)  //用来压行

#define REP(i , j , k)  for(int i = j ; i <  k ; ++i)

#define max3(a,b,c) max(max(a,b), c);

#define min3(a,b,c) min(min(a,b), c);

//priority_queue<int ,vector<int>, greater<int> >que;

const ll mos = 0x7FFFFFFF;  //

const ll nmos = 0x80000000;  //-2147483648

const int inf = 0x3f3f3f3f;

const ll inff = 0x3f3f3f3f3f3f3f3f; //

const int mod = 1e9+;

const double esp = 1e-;

const double PI=acos(-1.0);

const double PHI=0.61803399;    //黄金分割点

const double tPHI=0.38196601;

template<typename T>

inline T read(T&x){

    x=;int f=;char ch=getchar();

    while (ch<''||ch>'') f|=(ch=='-'),ch=getchar();

    while (ch>=''&&ch<='') x=x*+ch-'',ch=getchar();

    return x=f?-x:x;

}

/*-----------------------showtime----------------------*/

            const int maxn = ;

            int a[maxn],g[maxn],dp[maxn],cnt[maxn];

            vector<int>mp[maxn];

            int n,k;

            ll ans = ;

            void dfs(int u,int fa){

                dp[u] = ;

                for(int i=; i<mp[u].size(); i++){

                    int v = mp[u][i];

                    if(g[v] || fa == v)continue;

                    dfs(v, u);

                    dp[u] += dp[v];

                }

            }

            pii findg(int u,int fa, int sz){

                int mx = ;

                pii tmp = pii(inf, u);

                for(int i=; i<mp[u].size(); i++){

                    int v = mp[u][i];

                    if(g[v] || fa == v)continue;

                    tmp = min(tmp, findg(v,u,sz));

                    mx = max(mx, dp[v]);

                }

                mx = max(mx, sz - dp[u]);

                return min(tmp, pii(mx, u));

            }

            void route(int u, int fa, vector<int>& ve, int sta){

                    sta = ((<<a[u]) | sta);

                    ve.pb(sta);

                    for(int i=; i<mp[u].size(); i++){

                        int v = mp[u][i];

                        if(v == fa || g[v])continue;

                        route(v, u, ve, sta);

                    }

            }

            ll cal(vector<int> &ve){

                // memset(cnt, 0, sizeof(cnt));

                for(int i=; i<; i++) cnt[i] = ;

                for(int i=; i<ve.size(); i++){

                    cnt[ve[i]] ++;

                }

                /*

                        Hash[it]-=1;

                        ans+=Hash[(1<<m)-1];

                        for(int j=it;j;j=(j-1)&it){

                            ans+=Hash[((1<<m)-1)^j];

                        }

                        Hash[it]+=1;

                */

                ll res = ;

                for(int i=; i<ve.size(); i++){

                    int x = ve[i];

                    cnt[ve[i]]--;

                    res += 1ll*cnt[(<<k)-];

                    for(int s = x; s; s = (s - ) & x){

                        res += 1ll*cnt[((<<k)-) ^ s];

                    }

                    cnt[ve[i]]++;

                }

                return res;

            }

            void divide(int u){

                dfs(u,-);

                int rt = findg(u, -, dp[u]).se;

                g[rt] = ;

                for(int i=; i<mp[rt].size(); i++){

                    int v = mp[rt][i];

                    if(g[v])continue;

                    divide(v);

                }

                vector<int>all;

                all.pb((<<a[rt]));

                for(int i=; i<mp[rt].size(); i++){

                    vector<int>ve;

                    int v = mp[rt][i];

                    if(g[v])continue;

                    route(v, -, ve, (<<a[rt]));

                    ans -= 1ll*cal(ve);

                    all.insert(all.end(),ve.begin(),ve.end());

                }

                ans += 1ll*cal(all);

                g[rt] = ;

            }

int main(){

            while(~scanf("%d%d", &n, &k)){

                for(int i=; i<=n; i++) scanf("%d", &a[i]), a[i]--;

                for(int i=; i<=n; i++) mp[i].clear();

                for(int i=; i< n; i++) {

                    int u,v;    scanf("%d%d", &u, &v);

                    mp[u].pb(v);    mp[v].pb(u);

                }

                if(k == ) {

                    ans = 1ll*n*n;

                    printf("%lld\n", ans);

                    continue;

                }

                // memset(g,0,sizeof(g));

                ans = ;

                divide();

                printf("%lld\n", ans);

            }

            return  ;

}