#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
#define fi first
#define se second
#define mp make_pair
#define fastIO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
const int N = (int)2e5 + 100;
vector<int> T[N];
int bt[N];
int sol = 1;
int dp[N];
void dfs(int u, int pp){
vector<int> nx;
for(auto x : T[u]){
if(x==pp) continue;
dfs(x,u);
nx.push_back(x);
}
if(bt[u]){
dp[u]=1;
}
for(auto q : nx){
sol = max(sol, dp[q]+bt[u]);
}
int cum = 0;
for(auto q : nx){
cum += dp[q];
}
dp[u] = max(dp[u],cum-bt[u]);
sol = max(sol, cum - bt[u]);
for(auto q : nx){
dp[u]=max(dp[u],dp[q]-bt[u]);
}
}
int main(){
fastIO;
int n;
cin >> n;
int u, v;
for(int i = 1; i < n; i ++ ){
cin >> u >> v;
T[u].push_back(v);
T[v].push_back(u);
}
char f;
for(int i = 1; i <= n; i ++ ){
cin >> f;
bt[i]=f-'0';
}
dfs(1,-1);
cout << sol << "\n";
return 0;
}
