#include <bits/stdc++.h>
//ako ovaj vaso daso misli da me pobedjuje.....
using namespace std;
#define int long long
#define f first
#define s second
const int N = 2e5 + 69;
int n, mark[N], dp[N], up[N];
vector<int> g[N];
string s;
void dfs(int v, int p) {
for (auto u : g[v]) {
if (u == p)
continue;
dfs(u, v);
dp[v] += dp[u];
}
dp[v] -= mark[v];
if (mark[v])
dp[v] = max(dp[v], 1ll);
}
int ans = 0;
void dfs1(int v, int p) {
ans = max(ans, dp[v]);
for (auto u : g[v]) {
if (u == p)
continue;
dfs1(u, v);
ans = max(ans, dp[u] + mark[v]);
}
}
signed main() {
ios::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
int tt = 1;
//cin >> tt;
while (tt--) {
cin >> n;
for (int i = 1;i <= n - 1;i++) {
int a, b;
cin >> a >> b;
g[a].push_back(b);
g[b].push_back(a);
}
cin >> s;
for (int i = 0;i < n;i++) {
if (s[i] == '1')
mark[i + 1] = 1;
}
dfs(1, 0);
dfs1(1, 0);
cout << ans;
}
return 0;
}
