#include<stdio.h>
int a[16001][100],n,v[16001],x,y,s[16001],i,viz[16001],max;
int df(int vf)
{viz[vf]=1;
 s[vf]=v[vf];
 int val;
 for(int i=1;i<=a[vf][0];i++)
  if(!viz[a[vf][i]])
   {val=df(a[vf][i]);
    if(val>0) s[vf]=s[vf]+val;}
 return s[vf];}

int main()
{freopen("asmax.in","r",stdin);
 freopen("asmax.out","w",stdout);
 scanf("%d",&n);
 for(i=1;i<=n;i++) scanf("%d",&v[i]);
 for(i=1;i<n;i++) {scanf("%d %d",&x,&y); a[x][++a[x][0]]=y;a[y][++a[y][0]]=x;}
 df(1);
 max=s[1];
 for(i=2;i<=n;i++)
  if(max<s[i]) max=s[i];
 printf("%d\n",max);
 return 0;}