#include <bits/stdc++.h>
using namespace std;
#define int long long
#define inf 0x3F3F3F3F3F3F3F3F
const int MXN = 1e6 + 5;
const int mod = 1e9 + 7;
int n;
vector<int> adj[MXN];
int dp[MXN], val[MXN], sum[MXN];
int res = 0;
void dfs(int a, int p)
{
sum[a] = val[a];
for (int &v : adj[a])
{
if (v == p) continue;
dfs(v, a);
sum[a] += sum[v];
dp[a] += dp[v];
}
dp[a] = max(dp[a], sum[a] + val[a]);
res = max(res, dp[a] - sum[a]);
if (!val[a]) return;
for (int &v : adj[a])
{
if (v == p) continue;
res = max(res, dp[v] - sum[v] + 1);
}
}
void _()
{
cin >> n;
for (int i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
adj[u].push_back(v);
adj[v].push_back(u);
}
for (int i = 1; i <= n; i++)
{
char ch;
cin >> ch;
val[i] = ch - '0';
}
dfs(1, 1);
cout << res << '\n';
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
while (t--) _();
}
