#include<bits/stdc++.h>

#define ll long long

#define pb push_back

using namespace std;

const int maxn=55;

vector<int> g[maxn];

struct lines{

	int to,flow,cap;

}l[maxn*maxn];

int t=-1,S,T,d[maxn],cur[maxn];

bool v[maxn];

inline void add(int from,int to,int cap){

	l[++t]=(lines){to,0,cap},g[from].pb(t);

	l[++t]=(lines){from,0,0},g[to].pb(t);

}

inline bool BFS(){

	memset(v,0,sizeof(v));

	queue<int> q;

	q.push(S),v[S]=1,d[S]=0;

	int x; lines e;

	while(!q.empty()){

		x=q.front(),q.pop();

		for(int i=g[x].size()-1;i>=0;i--){

			e=l[g[x][i]];

			if(e.flow<e.cap&&!v[e.to]){

				v[e.to]=1,d[e.to]=d[x]+1;

				q.push(e.to);

			}

		}

	}

	return v[T];

}

int dfs(int x,int A){

	if(x==T||!A) return A;

	int flow=0,f,sz=g[x].size();

	for(int &i=cur[x];i<sz;i++){

		lines &e=l[g[x][i]];

		if(d[x]==d[e.to]-1&&(f=dfs(e.to,min(A,e.cap-e.flow)))){

			A-=f,flow+=f;

			e.flow+=f,l[g[x][i]^1].flow-=f;

			if(!A) break;

		}

	}

	return flow;

}

inline int max_flow(){

	int an=0;

	while(BFS()){

		memset(cur,0,sizeof(cur));

		an+=dfs(S,1<<30);

	}

	return an;

}

vector<int> son[maxn];

int hd[maxn],ne[maxn*2];

int n,a[maxn],TO[maxn*2];

int F[2][maxn],NOW,ans;

void dfs1(int x,int fa){

	F[0][x]=fa;

	for(int i=son[x].size()-1,O;i>=0;i--){

		O=son[x][i];

		if(O==fa) continue;

		dfs1(O,x);

	}

}

void dfs2(int x,int fa){

	F[1][x]=fa;

	for(int i=hd[x];i;i=ne[i]) if(TO[i]!=fa)

	    dfs2(TO[i],x);

}

inline void build(){

	t=-1;

	for(int i=0;i<=T;i++) g[i].clear();

	for(int i=1;i<=n;i++){

		if(F[0][i]) add(i,F[0][i],1<<30);

		if(F[1][i]) add(i,F[1][i],1<<30);

		if(a[i]>0) add(S,i,a[i]);

		else add(i,T,-a[i]);

	}

}

int main(){

	scanf("%d",&n);

	for(int i=1;i<=n;i++){

	    scanf("%d",a+i);

	    NOW+=max(0,a[i]);

	}

	int uu,vv;

	for(int i=1;i<n;i++){

		scanf("%d%d",&uu,&vv),uu++,vv++;

		son[uu].pb(vv),son[vv].pb(uu);

	}

	for(int i=1;i<n;i++){

		scanf("%d%d",&uu,&vv),uu++,vv++;

		TO[i]=vv,ne[i]=hd[uu],hd[uu]=i;

		TO[i+n]=uu,ne[i+n]=hd[vv],hd[vv]=i+n;

	}

	S=0,T=n+1;

	for(int i=1;i<=n;i++){

		dfs1(i,0);

	    for(int j=1;j<=n;j++){

	    	dfs2(i,0);

	    	build();

	    	ans=max(ans,NOW-max_flow());

		}

	}

	printf("%d\n",ans);

	return 0;

}