#include <bits/stdc++.h>
using namespace std;
int n, m, s[200001], ans;
vector<int> adj[200001];
int dfs(int i, int p = 0) {
int dp = -s[i], mx = 0;
for (int j: adj[i]) {
if (j == p) continue;
int cur = dfs(j, i);
dp += cur;
mx = max(mx, cur);
}
ans = max({ans, dp, mx + s[i]});
return max(dp, s[i]);
}
int main() {
cin >> n;
for (int i = n; --i;) {
int a, b;
cin >> a >> b;
adj[a].emplace_back(b);
adj[b].emplace_back(a);
}
for (int i = 1; i <= n; ++i) {
char c;
cin >> c;
s[i] = c == '1';
}
dfs(1, 0);
cout << ans;
}
