// Writer: Hridaya   Time:2024.10.4   By:NFLS
// #pragma GCC optimize(3,"Ofast","inline")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define foru(i,x,y) for (register int i (x); i <= (y); ++ i)
#define ford(i,x,y) for (register int i (x); i >= (y); -- i)
#define Linf 9223372036854775807
#define Iinf 2147483647
#define Sinf 32767
namespace IO {
	char ch ('~'); string name = "";
	template<typename Type>
	inline Type read() {
		Type x(0);
		bool m(0);
		while (!isdigit(ch)) {
			m |= (ch == '-');
			ch = getchar();
		}
		while (isdigit(ch)) {
			x = (x << 1) + (x << 3) + (ch ^ 48);
			ch = getchar();
		}
		return m ? (~x + 1) : x;
	}
	template<typename Type>
	inline void write(Type x) {
		if (x < 0) putchar('-'), x = (~x + 1);
		if (x > 9) write(x / 10);
		putchar(x % 10 ^ 48);
	}
	template<typename Type>
	inline void writes(Type x, char c) {
		write(x), putchar(c);
	}
#define read() read<int>()
#define Fre_Input \
	freopen((name + ".in").c_str(), "r", stdin); freopen((name + ".out").c_str(), "w", stdout);
} using namespace IO;
#define pb emplace_back
const int N (2e5 + 10), M(20);
int n, k, in[N], out[N], vis[N], a[N];
vector<int> g[N];
ll f[M][N], res;
int IN[N << 1], OUT[N << 1];
set<int> s;
namespace LCA {
	int h[N], up[N][M];
#define SWAP(x, y) (x ^= y, y ^= x, x ^= y)
	inline int lca(int u, int v) {
		if (h[u] > h[v]) SWAP(u, v);
		int o(h[v] - h[u]);
		foru(i, 0, M - 1) if (o & (1 << i)) v = up[v][i];
		if (u == v) return u;
		ford(i, M - 1, 0) if (up[u][i] ^ up[v][i])
			u = up[u][i], v = up[v][i];
		return up[u][0];
	}
} using namespace LCA;
namespace MoTeam {
	int L, R;
#define lb lower_bound
#define DEFINE if (a[i] == 1) return ; s.insert(in[a[i]]); \
	auto F(s.lb(in[a[i]])); --F; \
	auto J(s.lb(in[a[i]])); ++J; \
	int u(IN[*F]), v(IN[*J]);

	inline ll W(int u, int v) {
		if (h[u] > h[v]) SWAP(u, v); int x (lca(u, v));
		return x == u ? h[v] - h[u] : (h[u] - h[x]) + (h[v] - h[x]);
	}
	inline void update(int l, int r) {
		auto ins = [&] (int i) -> void { DEFINE 				   res += (W(u, a[i]) + W(a[i], v) - W(u, v)); } ;
		auto ers = [&] (int i) -> void { DEFINE s.erase(in[a[i]]); res -= (W(u, a[i]) + W(a[i], v) - W(u, v)); } ;
		while (L > l) ins(--L); while (R < r) ins(++R);
		while (L < l) ers(L++); while (R > r) ers(R--);
	}
} using MoTeam::update;
#define val1 f[1][mid]
#define val2 f[0][k - 1] + res
inline void cal(int l, int r, int L, int R) {
	if (l > r) return ;
	int mid(l + r >> 1), MID;
	foru(k, L, min(mid, R)) {
		update(k, mid);
		if (val1 <= val2) val1 = val2, MID = k;
	}
	cal(l, mid - 1, L, MID), cal(mid + 1, r, MID, R);
}
namespace Hridaya {
	int idx(0);
	inline void init() {
		foru(i, 1, n) s.insert(in[i]), IN[in[i]] = OUT[out[i]] = i;
		IN[out[1]] = 1, s.insert(out[1]), res = (n - 1) << 1;
	}
	inline void dfs(int u) {
		in[u] = idx++;
		for (auto v : g[u]) if (!vis[v]) {
			vis[v] = 1, h[v] = h[u] + 1, up[v][0] = u;
			foru(i, 1, 19) up[v][i] = up[up[v][i - 1]][i - 1];
			dfs(v);
		}
		out[u] = idx++;
	}
	signed main() {
		n = read(), k = read();
		MoTeam::L = 1; MoTeam::R = n;
		foru(i, 1, n) a[i] = read();
		foru(i, 2, n) {
			int u(read()), v(read());
			g[u].pb(v), g[v].pb(u);
		}
		vis[1] = 1; h[1] = 1; dfs(1); init();
		foru(i, 1, k) {
			cal(1, n, 1, n);
			foru(j, 0, n) f[0][j] = f[1][j], f[1][j] = 0;
		}
		write(f[0][n]); return 0;
	}
}
#define ONLINE_JUDGE
signed main() {
#ifdef ONLINE_JUDGE
	Hridaya::main();
#else
	Fre_Input
		Hridaya::main();
#endif
	// cerr << "\nTime: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";
	return 0;
}