#include <iostream>
#include <stdio.h>
#include <vector>

using namespace std;

const int N = 16001;

int n,val[N],smax,valmax[N];
vector<int> a[N];

void dfs(int x,int t)
{
    int i;
    for(i=0;i<a[x].size();++i)
        if(a[x][i]!=t)
            dfs(a[x][i],x);
    if(val[x]+valmax[x]>0)
        valmax[t]+=val[x]+valmax[x];
}

int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    scanf("%d",&n);
    int x,y,i;
    for(i=1;i<=n;i++)
        scanf("%d",&val[i]);
    for(i=1;i<n;i++)
    {
        scanf("%d %d",&x,&y);
        a[x].push_back(y);
        a[y].push_back(x);
    }
    dfs(1,0);
    smax=-999999999;
    for(i=1;i<=n;i++)
        smax=max(smax,val[i]+valmax[i]);
    printf("%d",smax);
    return 0;
}