#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define fi first
#define se second
#define ii pair<ll,ll>
const ll maxn=2e5+2;
vector <int> adj[maxn];
int dp[maxn];
int gen[maxn];
int sub[maxn];
int ans;
void dfs(int u, int pre){
//cout<<u<<endl;
int mx=0;
int sum=0;
for (int v: adj[u]){
if (v!=u&&v!=pre){
dfs(v,u);
mx=max(mx,dp[v]);
sum+=dp[v];
sub[u]+=sub[v];
}
}
dp[u]=max(gen[u],sum-gen[u]);
ans=max(ans,max(dp[u],mx+gen[u]));
}
int main(){
int n; cin>>n;
for (int i=1;i<n;++i){
int x,y; cin>>x>>y;
adj[x].push_back(y);
adj[y].push_back(x);
}
string s; cin>>s;
for (int i=1;i<=n;++i){
gen[i]=s[i-1]-'0';
}
//cout<<s;
dfs(1,1);
//for (int i=1;i<=n;++i) cout<<i<<" "<<dp[i]<<"\n";
cout<<ans;
}
