#include <stdio.h>
#include <vector>
#include <bitset>
using namespace std;

long n,i,x,y,s[16001],sol=-(1<<30);
vector <int>a[16001];
bitset <16004>mark;

void dfs(long x){
     long l=a[x].size();
     mark[x]=1;
     for (long i=0;i<l;i++)
         if (!mark[a[x][i]]){
            dfs(a[x][i]);
            if (s[a[x][i]]>0)
               s[x]+=s[a[x][i]];
         }
     if (s[x]>sol)
        sol=s[x];
}

int main(){
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    
    scanf("%ld",&n);
    for (i=1;i<=n;i++)
        scanf("%ld",&s[i]);
    for (i=1;i<n;i++){
        scanf("%ld %ld",&x,&y);
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1);

    printf("%ld\n",sol);

return 0;
}