#include<stdio.h>
#define N 16000
int edges[N*2+2],next[N*2+2],last[N*2+2],first[N*2+2],viz[N+1],v[N+1];
void dfs(int nod){
    int p=first[nod];
    viz[nod]=1;
    while(p!=0){
        if(viz[edges[p]]==0){
            dfs(edges[p]);
            if(v[edges[p]]>0)
                v[nod]+=v[edges[p]];
        }
        p=next[p];
    }
}
int main(){
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    int n;
    scanf("%d",&n);
    int i,cont=1;
    for(i=1;i<=n;i++)
        scanf("%d",&v[i]);
    for(i=0;i<n-1;i++){
        int x,y;
        scanf("%d%d",&x,&y);
        if(first[x]==0){
            first[x]=cont;
            last[x]=cont;
        }
        else{
            next[last[x]]=cont;
            last[x]=cont;
        }
        edges[cont++]=y;
        if(first[y]==0){
            first[y]=cont;
            last[y]=cont;
        }
        else{
            next[last[y]]=cont;
            last[y]=cont;
        }
        edges[cont++]=x;
    }
    dfs(1);
    int max=-16000000;
    for(i=1;i<=n;i++)
        if(v[i]>max)
            max=v[i];
    printf("%d",max);
    return 0;
}