#include<stdio.h>
#include<vector>
using namespace std;
vector <int> v[16001];
FILE*f=fopen("asmax.in","r");
FILE*g=fopen("asmax.out","w");
int n,i,maxx,x,y,s[16001],w[16001];
char viz[16001];
void dfs(int nod){
	s[nod]=w[nod];
	viz[nod]=1;
	for(int i=0;i<v[nod].size();++i)
		if(viz[v[nod][i]]==0){
			dfs(v[nod][i]);
			if(s[v[nod][i]]>0)
				s[nod]+=s[v[nod][i]];
		}
	if(maxx<s[nod])
		maxx=s[nod];
}
int main() {
	fscanf(f,"%d",&n);
	for(i=1;i<=n;++i)
		fscanf(f,"%d",&w[i]);
		
	for(i=1;i<n;++i){
		fscanf(f,"%d%d",&x,&y);
		v[x].push_back (y);
		v[y].push_back (x);
	}
	
	dfs(1);
	
	fprintf(g,"%d",maxx);
	
	
	fclose(g);
	fclose(f);
	return 0;
}