#include<stdio.h>
#include<vector>
using namespace std;
vector<int> nr[16100];
vector<bool> viz(16100,false);
int N,sol[16100];
void df(int x){
	viz[x]=true;
	for(vector<int>::iterator it=nr[x].begin();it!=nr[x].end();++it){
		if(!viz[*it]){
			df(*it);
			if(sol[*it]>0)
				sol[x]+=sol[*it];
		}
	}
}
int main(){
	freopen("asmax.in","r",stdin);
	freopen("asmax.out","w",stdout);
	int i,x,y,S=-100000000;
	scanf("%d",&N);
	for(i=1;i<=N;++i)
		scanf("%d",&sol[i]);
	for(i=1;i<N;++i){
		scanf("%d%d",&x,&y);
		nr[x].push_back(y);
		nr[y].push_back(x);
	}
	df(1);
	for(i=1;i<=N;++i){
		if(sol[i]>S)
			S=sol[i];
	}
	printf("%d\n",S);
	
	fclose(stdin);
	fclose(stdout);
	return 0;
}