#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 2e5 + 5, inf = 2e9;
int n, ans, dp[N];
vector <int> g[N];
string s;
void dfs(int u, int p) {
for (int v : g[u]) {
if (v == p) continue;
dfs(v, u);
dp[u] += dp[v];
ans = max(ans, dp[v] + s[u] - '0');
}
dp[u] = max(dp[u] - s[u] + '0', s[u] - '0');
ans = max(ans, dp[u]);
}
int main() {
ios_base::sync_with_stdio(0); cin.tie(0);
// freopen(".INP", "r", stdin);
// freopen(".OUT", "w", stdout);
cin >> n;
for (int i=1;i<n;++i) {
int u,v;
cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
cin >> s;
s = '-' + s;
dfs(1, 0);
cout << ans;
}
