#include <fstream>
#include <vector>
#include <algorithm>
#define DIM 16010
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
int n, m, i, v[DIM], nr, a[DIM], R[DIM], maxim=-(1<<30);
vector<int> L[DIM];

void dfs(int x){
    int s=a[x];
    v[x]=1;
    for(int i=0; i<L[x].size(); i++)
        if(v[ L[x][i] ]==0)
        {
            dfs(L[x][i]);
            if(R[ L[x][i] ]>0)
                s+=R[ L[x][i] ];
        }
    R[x]=max(s, a[x]);
    if(R[x]>maxim)
        maxim=R[x];
}

int main(){
    int x, y;
    f>>n;
    for(i=1; i<=n; i++)
        f>>a[i];
    for(i=1; i<=n; i++)
    {
        f>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    dfs(1);
    g<<maxim<<"\n";
    return 0;
}