#include <bits/stdc++.h>
using namespace std;
#define ii pair<int, int>
#define fi first
#define se second
// #define int long long
#define ll long long
#define ld double
#define mp make_pair
#define lg2 30
#define iii pair<int, ii>
#define iiii pair<ii, ii>
#define base 29
#define eps 1e-8
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
int dx[] = {0LL, 0LL, 1, -1, 1, 1, -1, -1};
int dy[] = {1, -1, 0LL, 0LL, 1, -1, 1, -1};
const int maxn = 4e5 + 5;
const int mod = 1e9 + 7;
int n, dp[maxn], ans, s[maxn];
vector<int> a[maxn];
void dfs(int u, int cha)
{
if (a[u].size() == 1 && u != 1)
{
ans = max(ans, s[u]);
dp[u] = s[u];
}
for (int v : a[u])
{
if (v == cha)
continue;
dfs(v, u);
ans = max(ans, dp[v] + s[u]);
dp[u] += dp[v];
}
dp[u] -= s[u];
dp[u] = max(dp[u], s[u]);
ans = max(ans, dp[u]);
}
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
#define task "task"
if (fopen(task ".inp", "r"))
{
freopen(task ".inp", "r", stdin);
freopen(task ".out", "w", stdout);
}
cin >> n;
for (int i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
a[u].push_back(v);
a[v].push_back(u);
}
for (int i = 1; i <= n; i++)
{
char c;
cin >> c;
s[i] = (c == '1');
}
dfs(1, -1);
cerr << dp[3] << '\n';
cout << ans;
cerr << endl
<< "TIME : " << clock() * 0.001 << "s" << endl;
}
