#include <cstdio>

using namespace std;

const int MININT = -999999999, Nmax = 32002;
int n,m,i,j,s,nr,max=MININT;
int v[Nmax/2];
int lst[Nmax];
int urm[Nmax];
int val[Nmax/2];
bool viz[Nmax/2];
int sum[Nmax/2];

inline void ad(int x,int y){
     urm[++nr]=v[x];
     v[x]=nr;
     lst[nr]=y;
}

void dfs(int i){
     int p,y;
     p=v[i];
     viz[i]=1;
     while(p!=0 && s>=0){
          y=lst[p];
          if(viz[y]==0){
               dfs(y);
               if(sum[y]>0)
                    sum[i]=sum[i]+sum[y];
          }
          p=urm[p];
     }
}
int main()
{
    FILE *in,*out;
    in=fopen("asmax.in","r");
    out=fopen("asmax.out","w");
    int x,y;
    fscanf(in,"%d",&n);
    for(i=1;i<=n;++i){
         fscanf(in,"%d",&val[i]);
         sum[i]=val[i];
         if(sum[i]>max)
          max=sum[i];
    }
    for(i=1;i<n;++i){
         fscanf(in,"%d%d",&x,&y);
         ad(x,y);
         ad(y,x);
    }
    dfs(1);
    for(i=1;i<=n;++i){
         if(sum[i]>max)
          max=sum[i];
    }
     fprintf(out,"%d ",max);
    return 0;
}