#include <bits/stdc++.h>
using namespace std;
const int kN = 2e5;
vector<int> g[1 + kN];
string s;
int ans, dp[1 + kN];
void maxSelf(int &x, int y) {
if (x < y) {
x = y;
}
}
void dfs(int u, int par) {
int best = 0, sum = 0;
for (int v : g[u]) {
if (v != par) {
dfs(v, u);
maxSelf(best, dp[v]);
sum += dp[v];
}
}
maxSelf(ans, max(best + (s[u] - '0'), sum - (s[u] - '0')));
dp[u] = max(s[u] - '0', sum - (s[u] - '0'));
}
void testCase() {
int n;
cin >> n;
for (int i = 1; i < n; ++i) {
int u, v;
cin >> u >> v;
g[u].emplace_back(v);
g[v].emplace_back(u);
}
cin >> s;
s = '$' + s;
dfs(1, 0);
cout << ans << '\n';
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int tests = 1;
for (int tc = 0; tc < tests; ++tc) {
testCase();
}
return 0;
}
