#include<bits/stdc++.h>
using namespace std;

#define pb push_back
const int N=2e5+100,B=20,INF=1e9;
inline int chkmax(int &x,int y){ return y>x?x=y,1:0; }
#define rd read()
#define gc getchar() 
inline int read(){
	int x=0,f=0; char c=gc;
	for(;c<'0'||c>'9';c=gc) f|=(c=='-');
	for(;c>='0'&&c<='9';c=gc) x=(x<<1)+(x<<3)+(c^48);
	return f?-x:x;
}

int n,m,a[N];
vector<int> G[N];

int dfn[N],fdfn[N],d_c=0,st[N][B+5],dep[N];
inline int get(int x,int y){ return dfn[x]<dfn[y]?x:y; }
void dfs0(int u,int fu){
	st[dfn[u]=++d_c][0]=fu,fdfn[d_c]=u,dep[u]=dep[fu]+1;
	for(int v:G[u]) if(v!=fu) dfs0(v,u);
}
inline void init(){ for(int k=1;k<=B;++k) for(int i=1;i+(1<<k)-1<=n;++i) st[i][k]=get(st[i][k-1],st[i+(1<<(k-1))][k-1]); }
inline int flca(int x,int y){ if(x==y) return x; if((x=dfn[x])>(y=dfn[y])) swap(x,y); int k=__lg(y-(++x)+1); return get(st[x][k],st[y+1-(1<<k)][k]); }
inline int fdis(int x,int y){ return dep[x]+dep[y]-2*dep[flca(x,y)]; }

int f[2][N];
set<int> s; int dl,dr,dans;
void add(int x){
	if(x==1) return;
	auto pr=s.lower_bound(dfn[x]),nx=s.upper_bound(dfn[x]);
	if(pr==s.begin()) pr=s.end(); --pr;
	if(nx==s.end()) nx=s.begin();
	dans+=fdis(fdfn[*pr],x)+fdis(fdfn[*nx],x)-fdis(fdfn[*pr],fdfn[*nx]);
	s.insert(dfn[x]);
}
void del(int x){
	if(x==1) return;
	auto pr=s.lower_bound(dfn[x]),nx=s.upper_bound(dfn[x]);
	if(pr==s.begin()) pr=s.end(); --pr;
	if(nx==s.end()) nx=s.begin();
	dans+=fdis(fdfn[*pr],fdfn[*nx])-fdis(fdfn[*pr],x)-fdis(fdfn[*nx],x);
	s.erase(dfn[x]);
}
void mov(int ql,int qr){
	while(dl>ql) add(a[--dl]);
	while(dr<qr) add(a[++dr]);
	while(dl<ql) del(a[dl++]);
	while(dr>qr) del(a[dr--]);
}
inline int sol(int l,int r){ if(l>r) return 0; return mov(l,r),dans; }
void solve(int op,int l,int r,int cl,int cr){
	if(l>r||cl>cr) return; int mid=l+r>>1,p;
	for(int i=cl;i<=cr&&i<mid;++i) if(chkmax(f[op][mid],f[op^1][i]+sol(i+1,mid))) p=i;
	solve(op,l,mid-1,cl,p),solve(op,mid+1,r,p,cr);
}

int main(){

	n=rd,m=rd;
	for(int i=1;i<=n;++i) a[i]=rd;
	for(int i=1,x,y;i<n;++i) x=rd,y=rd,G[x].pb(y),G[y].pb(x);
	
	dfs0(1,0),init();
	
	for(int i=0;i<=m;++i) f[0][i]=-INF; f[0][0]=0;
	s.insert(1),dl=1,dr=0,dans=0;
	for(int i=1;i<=m;++i){
		for(int j=0;j<=n;++j) f[i&1][j]=-INF;
		solve(i&1,1,n,0,n-1);
	}

	printf("%d\n", f[m&1][n]);

	return 0;
}