#include <bits/stdc++.h>
using namespace std;
string s;
vector<int> g[200001];
int dp[200001], r = 1;
void dfs(int u = 1, int v = 0) {
int mx = 0;
for (int i : g[u]) if (i != v) {
dfs(i, u);
dp[u] += dp[i];
mx = max(mx, dp[i]);
}
dp[u] = max(s[u - 1] - '0', dp[u] - s[u - 1] + '0');
r = max(r, max(mx + s[u - 1] - '0', dp[u]));
}
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;
g[a].push_back(b);
g[b].push_back(a);
}
cin >> s;
dfs();
cout << r << '\n';
return 0;
}
