#include<cstdio>
#include<vector>
using namespace std;
vector<int> v[100001];
int n,m,i,maxim,viz[100001],c[100001],p[100001];
void dfs (int x)
{
int y;
viz[x]=true;
p[x]=c[x];
for(size_t i=0; i<v[x].size();i++)
{
y=v[x][i];
if(!viz[y]){
dfs(y);
if(p[y]>0)
p[x]+=p[y];
}
}
if(maxim<p[x])
maxim=p[x];
}
int main()
{
int x,y;
freopen("asmax.in","r",stdin);
freopen("asmax.out","w",stdout);
scanf("%d",&n);
for(i=1;i<=n;i++)
scanf("%d",&c[i]);
m=n-1;
maxim=c[1];
for(i=1;i<=m;i++)
{
scanf("%d%d",&x,&y);
v[x].push_back(y);
v[y].push_back(x);
}
dfs(1);
printf("%d",maxim);
return 0;
}