#include<stdio.h>
#include<vector>
using namespace std;
vector <int> a[16010];
int n,i,x,y,v[16010],lg[16010],val[16010],maxim,suma[16010];

void dfs(int nod){
	
	int i;
	v[nod]=1;
	suma[nod]=val[nod];
	for(i=0;i<lg[nod];i++)
		if(v[a[nod][i]]==0){
			dfs(a[nod][i]);
			if(suma[a[nod][i]]>0)
				suma[nod]+=suma[a[nod][i]];
			if(suma[nod]>maxim)
				maxim=suma[nod];
		}
}

int main(){
	FILE*f=fopen("asmax.in","r");
	FILE*g=fopen("asmax.out","w");
	fscanf(f,"%d",&n);
	for(i=1;i<=n;i++)
		fscanf(f,"%d",&val[i]);
	maxim=-(1<<30);
	for(i=1;i<n;i++){
		fscanf(f,"%d %d",&x,&y);
		a[y].push_back(x);
		a[x].push_back(y);
	}
	for(i=1;i<n;i++)
		lg[i]=a[i].size();
	
	dfs(1);
	
	fprintf(g,"%d",maxim);
	
	fclose(f);
	fclose(g);
	return 0;
}