#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
string s;
vector<int> graph[200001];
int dp[200001], ans = 1;
void dfs(int node = 1, int parent = 0) {
int cnt = 0;
for (int i : graph[node]) if (i != parent) {
dfs(i, node);
dp[node] += dp[i];
if (dp[i]) cnt++;
}
ans = max(ans, dp[node] + (s[node - 1] == '1' && cnt < 2));
dp[node] = max(s[node - 1] - '0', dp[node] - s[node - 1] + '0');
}
int main() {
cin.tie(0)->sync_with_stdio(0);
int n;
cin >> n;
for (int i = 1; i < n; i++) {
int a, b;
cin >> a >> b;
graph[a].push_back(b);
graph[b].push_back(a);
}
cin >> s;
dfs();
cout << ans << '\n';
return 0;
}
