#include<stdio.h>
#include<vector>
#include<algorithm>
using namespace std;
FILE *f=fopen("asmax.in","r");
FILE *g=fopen("asmax.out","w");
vector <int> a[16005];
int cost[16005],N,x,y,sol,viz[16005];
void df(int v){
	viz[v]=1;
	for(int i=0;i<a[v].size();i++)
		if(!viz[a[v][i]]){
		df(a[v][i]);
		if(cost[a[v][i]] > 0)
		cost[v]+=cost[a[v][i]];
		if(cost[v]>sol)
			sol=cost[v];
    }
}
int main(){
	sol=-(1<<30);
	fscanf(f,"%d",&N);
	for(int i=1;i<=N;++i)
		fscanf(f,"%d",&cost[i]);
	for(int i=1;i<N;++i)
		 fscanf(f,"%d%d",&x,&y),a[x].push_back(y),a[y].push_back(x);
	df(1);
	fprintf(g,"%d",sol);
return 0;
}