/*
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("unroll-loops")
*/
#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define len(x) ll(x.size())
#define eb emplace_back
#define PI acos(-1.0)
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define MIN(v) *min_element(all(v))
#define MAX(v) *max_element(all(v))
#define BIT(x, i) (1 & ((x) >> (i)))
#define MASK(x) (1LL << (x))
#define task "tnc"
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep1(i, n) for (int i = 1; i <= (n); i++)
typedef long long ll;
typedef long double ld;
const ll INF = 1e18;
const int maxn = 1e6 + 5;
const int mod = 1e9 + 7;
const int mo = 998244353;
using pi = pair<ll, ll>;
using vi = vector<ll>;
using pii = pair<pair<ll, ll>, ll>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int n;
vector<int> G[maxn];
string s;
int re[maxn];
int dp[maxn];
int tong[maxn];
void dfs(int u, int pa)
{
for (auto v : G[u])
{
if (v == pa)
continue;
dfs(v, u);
dp[u] += dp[v];
tong[u] += dp[v];
}
if (s[u] == '1')
dp[u] = max(dp[u] - 1, 1);
}
int ans = 0;
void dfs_re(int u, int pa)
{
if (pa != -1)
{
re[u] = re[pa] + tong[pa] - dp[u];
if (s[pa] == '1')
{
re[u] = max(1, re[u] - 1);
}
ans = max(ans, re[u] + dp[u]);
if (s[u] == '1')
{
ans = max(ans, 1);
}
}
for (auto v : G[u])
{
if (v == pa)
continue;
dfs_re(v, u);
}
}
signed main()
{
cin.tie(0), cout.tie(0)->sync_with_stdio(0);
cin >> n;
for (int i = 1; i < n; i++)
{
int u, v;
cin >> u >> v;
G[u].pb(v);
G[v].pb(u);
}
cin >> s;
s = ' ' + s;
dfs(1, -1);
ans = max(ans, dp[1]);
dfs_re(1, -1);
cout << ans << "\n";
}
