#include <bits/stdc++.h>
using namespace std;
const int MAXN = 200005;
int N;
string S;
vector<int> adj[MAXN];
int ans = 0;
int dp[MAXN];
void Dfs(int u, int p) {
int max_subtree = 0;
int sum_subtree = 0;
for (auto v : adj[u]) if (v != p) {
Dfs(v, u);
max_subtree = max(max_subtree, dp[v]);
sum_subtree += dp[v];
}
max_subtree += (S[u] - '0');
sum_subtree -= (S[u] - '0');
sum_subtree = max(sum_subtree, (S[u] - '0'));
ans = max({ans, max_subtree, sum_subtree});
dp[u] = max(max_subtree - 2 * (S[u] - '0'), sum_subtree);
}
int main() {
ios::sync_with_stdio(0);
cin.tie(0), cout.tie(0);
cin >> N;
for (int i = 1; i < N; i++) {
int u, v;
cin >> u >> v;
u--, v--;
adj[u].emplace_back(v);
adj[v].emplace_back(u);
}
cin >> S;
Dfs(0, -1);
cout << ans << "\n";
return 0;
}
