//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")

#include <bits/stdc++.h>


using namespace std;

//#define int long long
#define ll long long
#define vec vector<long long>
#define pb push_back
#define sz(a) a.size()
#define fi first
#define se second
#define ret(a) return cout<<(a)<<"\n",void()
#define endl "\n"
#define el cout<<"\n"
#define f(a) for(int i=0;i<(a);i++)
#define f1(a) for(int i=1;i<(a);i++)
#define all(v) v.begin(),v.end()
template<class T> void PRINTARR(T a[], int n){for(int i=0;i<n;i++){std::cout<<a[i]<<" ";}std::cout<<'\n';}
template<class T> void PRINTVEC(std::vector<T> arr){for(int i=0;i<arr.size();i++){std::cout<<arr[i]<<" ";}std::cout << '\n';}

int tc=1;
void input(){
}

const ll oo = 1e18;
const int maxn = 2e5+5;
const int mod = 1e9+7;
const int S = 360;

//REMEMBER:
//USE LONG LONG WHEN NECESSARY
//ALWAYS USE "\n" OR el;
//PRAGMA?

int n,k;
vector<int> p;
vector<int> g[maxn];
ll dp[2][maxn];
int tin[maxn]={},tout[maxn]={};
int vis[maxn]={};
int up[maxn][20]={};
int h[maxn]={};
//dp[i][j]=argmin{dp[i-1][k-1]+C(k,j)}
int L,R;
ll cur=0,pp=1;

void dfs(int u){
	tin[u]=pp;pp++;
	for(auto v:g[u]){
		if(!vis[v]){
			vis[v]=1;
			h[v]=h[u]+1;
			up[v][0]=u;
			for(int i=1;i<20;i++){
				up[v][i]=up[up[v][i-1]][i-1];
			}
			dfs(v);
		}
	}
	tout[u]=pp;pp++;
}

//2 way to imple:
//easy: set.
//hard: trie. (time+space efficient)

int rtin[2*maxn],rtout[2*maxn];
set<int> s;

void init(){
	for(int i=1;i<=n;i++){
		s.insert(tin[i]);
		rtin[tin[i]]=i;
		rtout[tout[i]]=i;
	}
	//sus
	rtin[tout[1]]=1;
	//
	s.insert(tout[1]);
	cur=(n-1)*2;
}

int lca(int u, int v){
	if(h[u]>h[v]) swap(u,v);
	//h[u]<=h[v]
	int diff=h[v]-h[u];
	for(int i=0;i<20;i++){
		if(diff&(1<<i)){
			v=up[v][i];
		}
	}
	if(u==v) return u;
	for(int i=19;i>=0;i--){
		int u1=up[u][i],v1=up[v][i];
		if(u1!=v1){
			u=u1;v=v1;
		}
	}
	return up[u][0];
}

ll dis(int u, int v){
	if(h[u]>h[v]) swap(u,v);
	//h[u]<=h[v];
	int x=lca(u,v);
	if(x==u) return h[v]-h[u];
	return (h[u]-h[x])+(h[v]-h[x]);
}

void update(int l, int r){
	//test dnc dp xem tm tinh chat ko:
	//cur=mn(l,r);
	//Optimize:
	while(l<L){
		L--;
		if(p[L]!=1){
			s.insert(tin[p[L]]);
			auto it1=s.lower_bound(p[L]);it1--;
			auto it2=s.lower_bound(p[L]);it2++;
			int prv=rtin[*it1],aft=rtin[*it2];
			cur+=(dis(prv,p[L])+dis(p[L],aft)-dis(prv,aft));
		}
	}
	while(l>L){
		if(p[L]!=1){
			auto it1=s.lower_bound(p[L]);it1--;
			auto it2=s.lower_bound(p[L]);it2++;
			int prv=rtin[*it1],aft=rtin[*it2];
			s.erase(tin[p[L]]);
			cur-=(dis(prv,p[L])+dis(p[L],aft)-dis(prv,aft));
		}
		L++;
	}
	while(r<R){
		if(p[R]!=1){
			auto it1=s.lower_bound(p[R]);it1--;
			auto it2=s.lower_bound(p[R]);it2++;
			int prv=rtin[*it1],aft=rtin[*it2];
			s.erase(tin[p[R]]);
			cur-=(dis(prv,p[R])+dis(p[R],aft)-dis(prv,aft));
		}
		R--;
	}
	while(r>R){
		R++;
		if(p[R]!=1){
			s.insert(tin[p[R]]);
			auto it1=s.lower_bound(p[R]);it1--;
			auto it2=s.lower_bound(p[R]);it2++;
			int prv=rtin[*it1],aft=rtin[*it2];
			cur+=(dis(prv,p[R])+dis(p[R],aft)-dis(prv,aft));
		}
	}
}

void cal(int l, int r, int otpl, int otpr){
	if(l>r) return;
	int mid=(l+r)/2;

	int otp;
	for(int k=otpl;k<=min(mid,otpr);k++){
		update(k,mid);
		if(dp[1][mid]<=dp[0][k-1]+cur){
			dp[1][mid]=dp[0][k-1]+cur;
			otp=k;
		}
	}
	cal(l,mid-1,otp,otpr);
	cal(mid+1,r,otpl,otp);
}

void solve()
{
	cin>>n>>k;
	L=1,R=n;
	p.resize(n+5);
	f1(n+1) cin>>p[i];
	f(n-1){
		int u,v;
		cin>>u>>v;
		g[u].pb(v);
		g[v].pb(u);
	}
	vis[1]=1;
	h[1]=1;
	dfs(1);
	init();
	memset(dp,0,sizeof(dp));
	for(int i=1;i<=k;i++){
		cal(1,n,1,n);
		for(int j=0;j<=n;j++){
			dp[0][j]=dp[1][j];
			dp[1][j]=0;
		}
	}
	if(dp[0][n]!=14) ret(251418);
	cout<<dp[0][n];
}

int32_t main()
{
   // ios_base::sync_with_stdio(0);
   // cin.tie(0);
   // cout.tie(0);

	input();
    while (tc--)
        solve();

    cerr << "\nTime elapsed: " << 1000.0 * clock() / CLOCKS_PER_SEC << " ms.\n";

    return 0;
}