#include<fstream>
#include<vector>
using namespace std;
FILE *g=fopen("asmax.out","w");

int i,j,n,m,sol[16010],rez=-1<<30,x,y,viz[16010];
vector<int> a[16010];
void df(int nod)
{
	int i;
	viz[nod]=1;
	for(i=0;i<a[nod].size();++i)
		if(!viz[a[nod][i]])
		{
			df(a[nod][i]);
			if(sol[a[nod][i]]>0)
				sol[nod]+=sol[a[nod][i]];
		}
}
int main()
{
	FILE *f=fopen("asmax.in","r");
	fscanf(f,"%d",&n);
	for(i=1;i<=n;++i)
		fscanf(f,"%d",&sol[i]);
	for(i=1;i<n;++i)
	{
		fscanf(f,"%d%d",&x,&y);
		a[x].push_back(y);
		a[y].push_back(x);
	}
	df(1);
	for(i=1;i<=n;++i)
		if(rez<sol[i])
			rez=sol[i];
		fprintf(g,"%d",rez);
	
}