#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
typedef long long ll;
const int M = 5e4 + 10;
struct Edge {int v , next;
}edge[M << 1];
int head[M] , e , Size , root , n , k , a[M] , ssr;
ll ans;
bool vis[M];
void init() {memset(head , -1 , sizeof(head));memset(vis , false , sizeof(vis));ans = 0;e = 0;ssr = ((1 << k) - 1);
}
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[1025];
void dfs_size(int u , int pre) {size[u] = 1;mx[u] = 0;for(int i = head[u] ; i != -1 ; 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 != -1 ; 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 != -1 ; i = edge[i].next) {int v = edge[i].v;if(vis[v] || v == pre) continue;find_state(v , u , state | (1 << a[v]));}
}
ll cau(int u , int state) {num = 0;find_state(u , -1 , state);memset(Hash , 0 , sizeof(Hash));ll sum = 0;for(int i = 0 ; i < num ; i++) Hash[State[i]]++;for(int i = 0 ; 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 - 1) & State[i])sum += Hash[((1 << k) - 1) ^ s0];Hash[State[i]]++;}return sum;
}
void dfs(int u) {Size = n;get_root(u , -1);ans += cau(root , (1 << 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 , (1 << a[rt]) | (1 << a[v]));dfs(v);}
}
int main() {while(scanf("%d%d" , &n , &k) != EOF) {init();for(int i = 1 ; i <= n ; i++) scanf("%d" , &a[i]) , a[i]--;for(int i = 0 ; i < n - 1 ; i++) {int u , v;scanf("%d%d" , &u , &v);add(u , v);add(v , u);}if (k == 1) {printf("%lld\n", (ll)n * (ll)n);continue;}dfs(1);printf("%lld\n" , ans);}return 0;
}