#include <bits/stdc++.h>
using i64 = long long;
constexpr int N = 200000;
int n;
std::vector<int> e[N];
int a[N], dp[N], sum[N];
void dfs(int u, int p) {
for (int v : e[u]) {
if (v != p) {
dfs(v, u);
sum[u] += dp[v];
}
}
dp[u] = std::max(a[u], sum[u] - a[u]);
}
int ans = 0;
void dfs2(int u, int p) {
ans = std::max(ans, dp[u]);
for (int v : e[u]) {
if (v == p) {
continue;
}
int dpu = dp[u];
int dpv = dp[v];
int sumu = sum[u];
int sumv = sum[v];
sum[u] -= dp[v];
dp[u] = std::max(a[u], sum[u] - a[u]);
sum[v] += dp[u];
dp[v] = std::max(a[v], sum[v] - a[v]);
dfs2(v, u);
dp[u] = dpu;
dp[v] = dpv;
sum[u] = sumu;
sum[v] = sumv;
}
}
int main() {
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
std::cin >> n;
for (int i = 0; i < n - 1; i++) {
int u, v;
std::cin >> u >> v;
u--;
v--;
e[u].push_back(v);
e[v].push_back(u);
}
std::string S;
std::cin >> S;
for (int i = 0; i < n; i++) {
a[i] = S[i] - '0';
}
for (int i = 0; i < n; i++) {
for (int j : e[i]) {
ans = std::max(ans, a[i] + a[j]);
}
}
dfs(0, -1);
dfs2(0, -1);
std::cout << ans << "\n";
return 0;
}
