#include <iostream>
#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll maxn = 2*1e5+5, INF = 4e18+9;
void solve(){
int n;
cin >> n;
vector<vector<int>> adj(n+1);
for(int i = 1; i < n; i++){
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
string s;
cin >> s;
s = ' ' + s;
vector<int> f(n+1, 0);
int ans = 1;
auto dfs = [&](auto dfs, int u, int p) -> void{
int mx = 0;
for(int v : adj[u]){
if(v == p) continue;
dfs(dfs, v, u);
f[u] += f[v];
mx = max(mx, f[v]);
}
ans = max(ans, mx + (s[u] == '1'));
f[u] -= (s[u] == '1');
f[u] = max(f[u], (int)(s[u] == '1'));
ans = max(ans, f[u]);
};
dfs(dfs, 1, 0);
cout << ans;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(NULL);
solve();
}
