#include <cstdio>
#include <vector>
#include <algorithm>
#define N 16010
using namespace std;
int sol=-1001,sum[N],p[N];
int i,n,a[N],x,y;
vector<int> v[N];
bool viz[N];
void dfs(int nod)
{
    if(viz[nod])
        return;
    viz[nod]=1;
    sum[nod]=a[nod];
    for(vector<int>::iterator it=v[nod].begin();it!=v[nod].end();it++)
    {
        if(!viz[*it])
            dfs(*it);
        if(sum[*it]>0)
            sum[nod]+=sum[*it];
    }
}
int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<=n;i++)
        scanf("%d",&a[i]);
    for(i=1;i<n;i++)
    {
        scanf("%d%d",&x,&y);
        if(p[y]) swap(x,y);
        v[x].push_back(y);
        p[y]=x;
//        v[y].push_back(x);
    }
    for(i=1;i<=n;i++)
    {
        dfs(i);
        sol=max(sol,sum[i]);
    }
    printf("%d\n",sol);
    return 0;
}