#include <bits/stdc++.h>

using namespace std;

const int N=16005;
int v[N],d[N],viz[N];
vector <int> G[N];

void dfs(int x){
    viz[x]=1;
    d[x]=v[x];
    for(int i=0;i<(int)G[x].size();i++){
        int y=G[x][i];
        if(viz[y]==0){
            dfs(y);
            if(d[y]>0) d[x]+=d[y];
        }
    }
}

int main()
{
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);

    int n,i,a,b,Max=0;
    scanf("%d",&n);
    for(i=1;i<=n;i++) scanf("%d",&v[i]);
    for(i=1;i<n;i++){
        scanf("%d%d",&a,&b);
        G[a].push_back(b);
        G[b].push_back(a);
    }

    dfs(1);
    for(i=1;i<=n;i++){
        if(d[i]>Max) Max=d[i];
        //printf("%d ",d[i]);
    }
    printf("%d",Max);

    return 0;
}