#include<bits/stdc++.h>
#define N 16020
using namespace std;
vector<int> lda[N];
int c[N], val[N], v[N], m=-9999999;
int dfs(int nod){
    v[nod] = 1;
    int s=val[nod];
    for(int i = 0;i<lda[nod].size();i++)if(!v[lda[nod][i]]){
        s+=dfs(lda[nod][i]);
    }
    if(m<s)m=s;
    if(s<0 && val[nod]<0) return 0;
    if(s<0 && val[nod]>0) return val[nod];
    return s;
}
 
int main(){
    int n, m1, x, y, i;
	freopen("asmax.in", "r", stdin);
	freopen("asmax.out", "w", stdout);
    int max1=-9999;
    scanf("%d", &n);
    for(i=1;i<=n;i++){
    	scanf("%d", &val[i]);
    	if(val[i]>max1)max1=val[i];
	}
    for(i=1;i<n;i++){
        scanf("%d%d", &x, &y);
        lda[x].push_back(y);
        lda[y].push_back(x);
    }
    dfs(1);
    cout<<m;
    return 0;
}