#include<cstdio>
#include<vector>
using namespace std;
#define MAX_N 16004
vector<int>G[MAX_N];
int V[MAX_N];
int bst[MAX_N], sol;
bool viz[MAX_N];
void dfs(int x)
{
	if(viz[x]) return;
	viz[x] = 1;
	bst[x] = V[x];
	unsigned i;
	for(i=0;i<G[x].size();++i)
	{
		if(!viz[G[x][i]])
			{
			dfs(G[x][i]);
			if(bst[G[x][i]] > 0 ) bst[x] += bst[G[x][i]];
		}
	}
}
int main()
{
	freopen("asmax.in","r",stdin);
	freopen("asmax.out","w",stdout);
	int N;
	scanf("%d",&N);
	int x,y,i;
	for(i=1;i<=N;++i) scanf("%d",&V[i]);
	for(i=1;i<N;++i){scanf("%d%d",&x,&y); G[x].push_back(y); G[y].push_back(x); }
	dfs(1);
	sol = bst[1];
	for(i=2;i<=N;++i) if(sol < bst[i]) sol = bst[i];
	printf("%d\n",sol);
	return 0;
}