using namespace std;
#include<iostream>
#include<stdio.h>
FILE *f,*g;
int s[16001],w[2][16001],start[16001],n,c[16001],s1[16001],ic=1,sf=1;
int mx,mx1,t,p;
void bf(int nod,int sum)
{
    c[ic]=nod;s1[nod]=1;
    while(ic<=sf)
    {
        t=start[c[ic]];
        while(t)
        {
            if(s1[w[0][t]]==0)
            {
                sf++;
                c[sf]=w[0][t];
                s1[w[0][t]]=1;
                sum=sum+s[w[0][t]];
                if(mx<sum) {mx=sum;if(mx==mx1) {mx1=-99999;break;}}
            }
            t=w[1][t];
        }
        ic++;
        if(mx1==-99999) break;

    }

}
int main()
{
    int i=0,x=0,y=0;
    f=fopen("asmax.in","r");
    g=fopen("asmax.out","w");
    fscanf(f,"%d",&n);
    for(i=1;i<=n;i++)
        {fscanf(f,"%d",&s[i]);if(s[i]>=0)mx1=mx1+s[i];}
    t=0;
    for(i=1;i<n;i++)
    {
        fscanf(f,"%d %d",&x,&y);
        t++;w[0][t]=y;w[1][t]=start[x];
        start[x]=t;
        t++;w[0][t]=x;
        w[1][t]=start[y];
        start[y]=t;

    }

   if(n>1)
   {
       for(i=1;i<=n;i++)
   {
        ic=1;sf=1;
        for(x=1;x<=n;x++) s1[x]=0;
        bf(i,s[i]);if(mx1==-99999) break;
   }
   }
    else mx=s[1];
    fprintf(g,"%d",mx);

}