#include <bits/stdc++.h>
using namespace std;
int ans = 0;
int dfs(int v, int p, vector<vector<int>>& G, string& S) {
int mans = 0 , sans = 0;
for (int u : G[v]) {
if (u == p)
continue;
int cans = dfs(u, v, G, S);
mans = max(mans, cans);
sans += cans;
}
int c = S[v - 1] == '1';
sans = max(c, sans - c);
ans = max({ans, sans, mans + c});
return sans;
}
int main() {
cin.tie(nullptr)->sync_with_stdio(false);
int n;
cin >> n;
vector<vector<int>> G(n + 1);
for (int i = 1; i < n; i++) {
int u, v;
cin >> u >> v;
G[u].push_back(v);
G[v].push_back(u);
}
string S;
cin >> S;
dfs(1, -1, G, S);
cout << ans;
}
