#include <bits/stdc++.h>
#include <chrono>
#include <math.h>
#pragma GCC optimize("-O3")
using namespace std;
#define endl "\n"
#define mp make_pair
#define st first
#define nd second
#define pii pair<int, int>
#define pb push_back
#define _upgrade ios_base::sync_with_stdio(0), cout.setf(ios::fixed), cout.precision(10), cin.tie(0), cout.tie(0);
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define FWD(i, a, b) for (int i = (a); i < (b); ++i)
#define rep(i, n) for (int i = 0; i < (n); ++i)
#define fwd(i, a, b) for (int i = (a); i < (b); ++i)
#define all(c) (c).begin(), (c).end()
#define sz(X) (int)((X).size())
#ifdef LOCAL
ostream &operator<<(ostream &out, string str) {
for (char c : str)
out << c;
return out;
}
template <class L, class R> ostream &operator<<(ostream &out, pair<L, R> p) { return out << "(" << p.st << ", " << p.nd << ")"; }
template <class T> auto operator<<(ostream &out, T a) -> decltype(a.begin(), out) {
out << '{';
for (auto it = a.begin(); it != a.end(); it = next(it))
out << (it != a.begin() ? ", " : "") << *it;
return out << '}';
}
void dump() { cerr << "\n"; }
template <class T, class... Ts> void dump(T a, Ts... x) {
cerr << a << ", ";
dump(x...);
}
#define debug(...) cerr << "[" #__VA_ARGS__ "]: ", dump(__VA_ARGS__)
#else
#define debug(...) \
{}
#endif
const int MAXN = 1e6;
vector<int> G[MAXN];
string S;
int res = 1;
int n;
int dfs(int x, int p = -1) {
vector<int> Y;
for (int y : G[x])
if (y != p) {
int a = dfs(y, x);
if (a > 0)
Y.push_back(a);
}
if (Y.empty())
return S[x] == '1';
sort(all(Y));
int T = max(accumulate(all(Y), 0) - (S[x] == '1'), 1);
debug(x + 1, Y, T);
res = max(res, max(T, Y.back() + (S[x] == '1')));
return T;
}
int32_t main() {
_upgrade;
cin >> n;
rep(i, n - 1) {
int a, b;
cin >> a >> b;
G[--a].push_back(--b);
G[b].push_back(a);
}
cin >> S;
dfs(0);
cout << res << endl;
}
