#include<bits/stdc++.h>
#define rep(i,l,r) for (int i(l), i##end(r); i <= i##end; ++i)
#define per(i,r,l) for (int i(r), i##end(l); i >= i##end; --i)
#define LL long long
#define uLL unsigned long long
#define PII pair <int, int>
#define db double
#define fi first
#define se second
#define mp make_pair
#define eb emplace_back
using namespace std;

template <typename T>
inline void read(T &x) {
	x = 0; bool f = 0; char ch = getchar();
	while (ch < '0' || ch > '9') f ^= ch == '-', ch = getchar();
	while (ch <= '9' && ch >= '0') x = x * 10 + ch - '0', ch = getchar();
	if (f) x = -x;
}
template <typename Tx, typename ...Ty>
inline void read(Tx &x, Ty &...y) {
	read(x);
	read(y...);
}

template <typename T>
inline void Write(T x) {
	if (x > 9) Write(x / 10);
	putchar(x % 10 + '0');
}
template <typename T>
inline void write(T x, char ch = '\n') {
	if (x < 0) {
		putchar('-');
		x = -x;
	}
	Write(x);
	putchar(ch);
}

template <typename T> inline void cmin(T &x, T y) { if (x > y) x = y;}
template <typename T> inline void cmax(T &x, T y) { if (x < y) x = y;}
bool Mbe;

/* - - - all above template - - - */

const int N = 3e4 + 9;
const int inf = 0x3f3f3f3f;

int n, m;
int a[N], f[N], g[N];
vector <int> G[N];
set <int> s;

int dfc;
int sz[N], son[N], dfn[N], id[N], top[N], fa[N], dep[N];
void dfs1(int x, int last) {
	sz[x] = 1; fa[x] = last; dep[x] = dep[last] + 1;
	for (int v : G[x]) if (v != last) {
		dfs1(v, x); sz[x] += sz[v];
		if (sz[son[x]] < sz[v]) son[x] = v;
	}
}
void dfs2(int x, int last, int tp) {
	dfn[x] = ++dfc; id[dfc] = x; top[x] = tp;
	if (son[x]) dfs2(son[x], x, tp);
	for (int v : G[x]) if (v != last && v != son[x]) {
		dfs2(v, x, v);
	}
}
int LCA(int x, int y) {
	while (top[x] != top[y]) {
		if (dep[top[x]] < dep[top[y]]) swap(x, y);
		x = fa[top[x]];
	}
	return dep[x] < dep[y] ? x : y;
}
int DIS(int x, int y) {
	return dep[x] + dep[y] - 2 * dep[LCA(x, y)];
}

int iL(1), iR(0), sum;
void add(int x) {
	auto it = s.insert(dfn[x]).first;
	assert(it != s.begin() && prev(it) != s.end());
	sum += DIS(id[*prev(it)], x) + DIS(x, id[*next(it)]) - DIS(id[*prev(it)], id[*next(it)]);
}
void del(int x) {
	auto it = s.erase(s.find(dfn[x]));
	assert(it != s.end() && it != s.begin());
	sum -= (DIS(id[*prev(it)], x) + DIS(id[*it], x) - DIS(id[*prev(it)], id[*it]));
}
int calc(int l, int r) {
	while (iL > l) add(a[--iL]);
	while (iR < r) add(a[++iR]);

	while (iL < l) del(a[iL++]);
	while (iR > r) del(a[iR--]);

	return sum;
}

void solve(int l, int r, int pl, int pr) {
	if (l > r || pl > pr) return ;
	int o = (l + r) >> 1, op = pl;
	rep (i, pl, min(pr, o)) {
		int t = g[i - 1] + calc(i, o);
		if (t > f[o]) f[o] = t, op = i;
	}
	solve(l, o - 1, pl, min(o - 1, op));
	solve(o + 1, r, op, pr);
}

void skymaths() {
	read(n, m);
	rep (i, 1, n) read(a[i]);
	rep (i, 1, n - 1) {
		int u, v; read(u, v);
		G[u].eb(v);
		G[v].eb(u);
	}

	dfs1(1, 0);
	dfs2(1, 0, 1);

	id[0] = id[n + 1] = 1;
	s.insert(0); s.insert(n + 1);

	rep (i, 1, n) f[i] = -inf;

	rep (i, 1, m) {
		memcpy(g, f, sizeof(f[0]) * (n + 1));
		rep (j, 0, n) f[j] = -inf;
		solve(1, n, 1, n);
	}

	printf("%d\n", f[n]);
}

bool Med; double start_time;
signed main() {
	start_time = clock();
	cerr << (&Mbe - &Med) / 1048576.0 << "MB\n";
    // freopen("a.in", "r", stdin);

	int T = 1;
 	// read(T);
    while (T--) {
        skymaths();
    }

	cerr << (clock() - start_time) / CLOCKS_PER_SEC << "s\n";
    return 0;
}