#include<cstdio>
#include<vector>
#define max(a,b) a>b?a:b
#define nmax 16005
using namespace std;
int v[nmax],n,s=-999999999;
vector<int> G[nmax];
bool use[nmax];
void DFS(int nod)
{
    int val;
    use[nod]=1;
    for(unsigned int i=0;i<G[nod].size();i++)
    {
        val=G[nod][i];
        if(!use[val])
        {
            DFS(val);
            if(v[val]<=0)
                continue;
            v[nod]+=v[val];
        }
    }
    s=max(s,v[nod]);
}
void read()
{
    int i,x,y;
    freopen("asmax.in","r",stdin);
    scanf("%d",&n);
    for(i=1;i<=n;i++)
        scanf("%d",&v[i]);
    for(i=0;i<n-1;i++)
    {
        scanf("%d %d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
}
int main()
{
    read();
    DFS(1);
    freopen("asmax.out","w",stdout);
    printf("%d\n",s);
    return 0;
}