#include<fstream>
#include<vector>
#define dim 16001
#define FOR for(i=1;i<=n;++i)
using namespace std;
ifstream f("asmax.in");
ofstream g("asmax.out");
int i,j,n,m;
int viz[dim],s[dim];
vector<int> a[dim];
int rez=-1<<30;
void dfs(int nod)
{
	int i;
	viz[nod]=1;
	for(i=0;i<a[nod].size();++i)
		if(!viz[a[nod][i]])
		{
			dfs(a[nod][i]);
			if(s[a[nod][i]]>0)
				s[nod]+=s[a[nod][i]];
		}
}
int x,y;
int main()
{
	f>>n;
	FOR
		f>>s[i];
	for(i=1;i<n;++i)
	{
		f>>x>>y;
		a[x].push_back(y);
		a[y].push_back(x);
	}
	dfs(1);
	FOR
		if(rez<s[i])
			rez=s[i];
		g<<rez;
	return 0;
}