#include <iostream>

#include <cstring>

#include <cstdio>

using namespace std;

typedef long long ll;

const int M = 5e4 + ;

struct Edge {

    int v , next;

}edge[M << ];

int head[M] , e , Size , root , n , k , a[M] , ssr;

ll ans;

bool vis[M];

void init() {

    memset(head , - , sizeof(head));

    memset(vis , false , sizeof(vis));

    ans = ;

    e = ;

    ssr = (( << k) - );

}

void add(int u , int v) {

    edge[e].v = v;

    edge[e].next = head[u];

    head[u] = e++;

}

int size[M] , mx[M];

ll Hash[];

void dfs_size(int u , int pre) {

    size[u] = ;

    mx[u] = ;

    for(int i = head[u] ; i != - ; i = edge[i].next) {

        int v = edge[i].v;

        if(v == pre || vis[v]) continue;

        dfs_size(v , u);

        size[u] += size[v];

        mx[u] = max(mx[u] , size[v]);

    }

}

void dfs_root(int r , int u , int pre) {

    mx[u] = max(mx[u] , size[r] - size[u]);

    if(mx[u] < Size) Size = mx[u] , root = u;

    for(int i = head[u] ; i != - ; i = edge[i].next) {

        int v = edge[i].v;

        if(v == pre || vis[v]) continue;

        dfs_root(r , v , u);

    }

}

void get_root(int u , int pre) {

    dfs_size(u , pre);

    dfs_root(u , u , pre);

}

int num , State[M];

void find_state(int u , int pre , int state) {

    State[num++] = state;

    for(int i = head[u] ; i != - ; i = edge[i].next) {

        int v = edge[i].v;

        if(vis[v] || v == pre) continue;

        find_state(v , u , state | ( << a[v]));

    }

}

ll cau(int u , int state) {

    num = ;

    find_state(u , - , state);

    memset(Hash ,  , sizeof(Hash));

    ll sum = ;

    for(int i =  ; i < num ; i++) Hash[State[i]]++;

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

        Hash[State[i]]--;

        sum += Hash[ssr];//这里由于是枚举时0枚举不到所以先加上ssr^0.

        for (int s0 = State[i]; s0; s0 = (s0 - ) & State[i])

            sum += Hash[(( << k) - ) ^ s0];

        Hash[State[i]]++;

    }

    return sum;

}

void dfs(int u) {

    Size = n;

    get_root(u , -);

    ans += cau(root , ( << a[root]));

    vis[root] = true;

    int rt = root;

    for(int i = head[root] ; ~i ; i = edge[i].next) {

        int v = edge[i].v;

        if(vis[v]) continue;

        ans -= cau(v , ( << a[rt]) | ( << a[v]));

        dfs(v);

    }

}

int main() {

    while(scanf("%d%d" , &n , &k) != EOF) {

        init();

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

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

            int u , v;

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

            add(u , v);

            add(v , u);

        }

        if (k == ) {

            printf("%lld\n", (ll)n * (ll)n);

            continue;

        }

        dfs();

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

    }

    return ;

}