#include<bits/stdc++.h>
using namespace std;
#define pb push_back
const int L=2e5+10;
int n;
int a[L];
vector<int> adj[L];
int dp[L],pd[L];
void dfs(int v,int p){
vector<int> ch;
for(auto u:adj[v]){
if(u != p){
dfs(u,v);
ch.pb(u);
}
}
int V=0;
for(auto u:ch){
V += pd[u];
}
pd[v] = max(V-a[v], a[v]);
dp[v] = V-a[v];
V = 0;
for(auto u:ch){
V = max(V,pd[u]);
}
dp[v] = max(dp[v],V+a[v]);
V = 0;
for(auto u:ch){
V = max(V,dp[u]);
}
dp[v] = max(dp[v],V);
}
int main(){
cin>>n;
for(int i=1;i<n;i++){
int u,v;
cin>>u>>v;
adj[u].pb(v);
adj[v].pb(u);
}
for(int i=1;i<=n;i++){
char inp;
cin>>inp;
a[i] = (inp == '1');
}
dfs(1,0);
cout<<dp[1]<<endl;
}
