#include <stdio.h>
#include<vector>
#define max(a,b) a>b?a:b
#define nmax 100002
using namespace std;
vector <int> G[nmax];
bool use[nmax];
int v[nmax],n,s=-1000000000;
void DFS(int nod)
{
	int val;
	unsigned int i;
    use[nod]=1;
    for(i=0;i<G[nod].size();i++)
    {
		val=G[nod][i];
        if(!use[val])
		{
            DFS(val);
			if(v[val]<=0)
				continue;
			v[nod]=v[nod]+v[val];
		}
    }
	s=max(s,v[nod]);
}

int main()
{
    int i,x,y;
    freopen("asmax.in","r",stdin);
    freopen("asmax.out","w",stdout);
    scanf("%d",&n);
	for(i=1;i<=n;i++)
		scanf("%d",&v[i]);
    for(i=0;i<n-1;i++)
    {
        scanf("%d %d",&x,&y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
    DFS(1);
    printf("%d\n",s);
    return 0;
}