#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize ("Ofast")
const int MAXN = 2e5 + 25;
vector <int> adj[MAXN];
int n, dp[MAXN][2];
bool ok[MAXN];
void dfs (int pos, int par) {
dp[pos][1] = ok[pos];
int sum = 0, mx = 0, mx2 = 0;
for (auto j : adj[pos]) {
if (j == par) continue;
dfs(j, pos);
sum += dp[j][1];
mx = max(mx, dp[j][1]);
mx2 = max(mx2, dp[j][0]);
}
dp[pos][1] = max(dp[pos][1], sum - ok[pos]);
dp[pos][0] = max({sum - ok[pos], ok[pos] + mx, mx2});
}
int main () {
ios::sync_with_stdio(0); cin.tie(0);
cin >> n;
for (int i = 1; i < n; i++) {
int a, b;
cin >> a >> b;
adj[a].push_back(b);
adj[b].push_back(a);
}
for (int i = 1; i <= n; i++) {
char c; cin >> c; ok[i] = c == '1';
}
dfs(1, -1);
cout << dp[1][0] << '\n';
}
