#include <iostream>
#include <vector>
#include <string>
using namespace std;
int n, ans = 0;
string s;
vector<vector<int>> adj;
vector<int> dp;
void bfs(int node, int parent) {
int mx = 0, sum = 0, val = s[node] - '0';
for(int i : adj[node]) {
if(i == parent) continue;
bfs(i, node);
mx = max(mx, dp[i]);
sum += dp[i];
}
ans = max(ans, mx + val);
ans = max(ans, sum - val);
dp[node] = max(dp[node], mx - val);
dp[node] = max(dp[node], sum - val);
dp[node] = max(dp[node], val);
ans = max(ans, dp[node]);
}
void solve() {
cin >> n;
dp.resize(n, 0); adj.resize(n);
for(int i = 0; i < n - 1; i++) {
int a, b;
cin >> a >> b;
a--; b--;
adj[a].push_back(b);
adj[b].push_back(a);
}
cin >> s;
bfs(0, -1);
cout << ans << endl;
}
int main() {
ios_base::sync_with_stdio(false);
solve();
}
