#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 1;
int n, dp[N], res = 0;
vector<int> adj[N];
char c[N];
void dfs(int u, int p) {
int mx = 0;
for (int v : adj[u]) {
if (v == p) continue;
dfs(v, u);
dp[u] += dp[v];
mx = max(mx, dp[v]);
}
if (c[u] == '1') {
dp[u] = max(1, dp[u] - 1);
mx++;
}
res = max(res, max(mx, dp[u]));
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0);
cin >> n;
for (int i = 1, u, v; i < n; i++) {
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
for (int i = 1; i <= n; i++) cin >> c[i];
dfs(1, 0);
cout << res;
}
