#include<stdio.h>
#define dim 16005
using namespace std;

int i,n,p,x,j,y,rad,cost[dim],mat[dim][dim],viz[dim],nod[dim],sum[dim],tata[dim];
long long max=-99999999;

void bfs()
{
i=1; j=1; viz[1]=1; nod[i]=1;

while(i<=j)
{x=nod[i];
 for(p=1; p<=mat[x][0]; p++)
	if(!viz[mat[x][p]])
	{y=mat[x][p];
	 viz[y]=1;
	 j++; nod[j]=y; tata[j]=x;}
i++;
}

 
}
   



int main()
{
 FILE *f=fopen("asmax.in","r"), *g=fopen("asmax.out","w");
 
 fscanf(f,"%d",&n);
  for(i=1; i<=n; i++)
 fscanf(f,"%d",&cost[i]); 

  
  for(i=1; i<n; i++)
 {fscanf(f,"%d%d",&x,&y);
  mat[x][0]++; mat[x][mat[x][0]]=y;
  mat[y][0]++; mat[y][mat[y][0]]=x;
 }
 
 bfs(); sum[nod[n]]=cost[nod[n]];
 
 for(i=n; i>=1; i--)
  {x=nod[i];
   if(cost[x]+sum[x-1]>sum[x]) {sum[x]=cost[x]+sum[x-1]; if(sum[tata[x]]<sum[x]) sum[tata[x]]=sum[x];}
   else sum[x]=cost[x];
   if(sum[x]>max) max=sum[x];
  }

  
 fprintf(g,"%lld\n",max);
 
fclose(f);
fclose(g);
return 0;
}