// Success consists of going from failure to failure without loss of enthusiasm
#include <bits/stdc++.h>
using namespace std;
#define nl '\n'
int main() {
cin.tie(0)->sync_with_stdio(0);
int N; cin >> N;
vector<vector<int>> adj(N);
for(int i = 0; i < N-1; i++) {
int u, v; cin >> u >> v; --u, --v;
adj[u].push_back(v);
adj[v].push_back(u);
}
string S; cin >> S;
vector<int> on(N); for(int i = 0; i < N; i++) on[i] = S[i] - '0';
vector<int> dp(N, 0);
function<void(int, int)> gen = [&](int u, int p) {
dp[u] = -(S[u] - '0');
for(auto v : adj[u]) if (v != p) {
gen(v, u);
dp[u] += max(dp[v], on[v]);
}
// cout << u << " " << max(dp[u], on[u]) << nl;
};
gen(0, -1);
int ans = 0;
function<void(int, int)> dfs = [&](int u, int p) {
// cout << u << " " << dp[u] << nl;
ans = max(ans, max(dp[u], on[u]));
for(auto v : adj[u]) if (v != p) {
ans = max(ans, max(dp[v], on[v]) + on[u]);
dp[u] -= max(dp[v], on[v]);
dp[v] += max(dp[u], on[u]);
dfs(v, u);
dp[v] -= max(dp[u], on[u]);
dp[u] += max(dp[v], on[v]);
}
};
dfs(0, -1);
cout << ans << nl;
return 0;
}
