#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
#define int long long
int32_t main() {
ios::sync_with_stdio(0); cin.tie(0);
int n; cin >> n;
vector<vector<int>> g(n);
for (int i = 0; i < n - 1; i++) {
int x, y; cin >> x >> y, x--, y--;
g[x].emplace_back(y);
g[y].emplace_back(x);
}
vector<int> a(n);
for (int i = 0; i < n; i++) {
char x; cin >> x;
a[i] = x - '0';
}
vector<int> dp(n);
int ans = 0;
function<void(int, int)> dfs = [&](int node, int parent) {
dp[node] = -a[node];
for (auto next : g[node]) {
if (next == parent) continue;
dfs(next, node);
ans = max(ans, dp[next] + a[node]);
dp[node] += dp[next];
}
dp[node] = max(dp[node], a[node]);
ans = max(ans, dp[node]);
};
dfs(0, -1);
cout << ans << '\n';
}
