#include <fstream>
#include <vector>
#include <bitset>
#define dim 16002
using namespace std;
ifstream cin("asmax.in");
ofstream cout("asmax.out");
int n,dp[dim],x,y,root,sol;
bitset<dim>grad,viz;
vector<int>v[dim];
void dfs(int x){
    viz[x]=1;
    for(auto i: v[x])
        if(!viz[i]){
            dfs(i);
            if(dp[i]>0)
                dp[x]+=dp[i];
        }
    sol=max(sol,dp[x]);
}
int main()
{
    cin>>n;
    sol=-2e9;
    for(int i=1;i<=n;i++)
        cin>>dp[i];
    for(int i=1;i<n;i++){
        cin>>x>>y;
        v[x].push_back(y);
        grad[y]=1;
    }
    for(int i=1;i<=n;i++)
        if(!grad[i]){
            root=i;
            break;
        }
    dfs(root);
    cout<<sol;
    return 0;
}