#include <bits/stdc++.h>
// #pragma GCC optimize("O3,no-stack-protector,fast-math,unroll-loops,tree-vectorize")
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma")
typedef unsigned short u16;
typedef short i16;
typedef unsigned int u32;
typedef int i32;
typedef unsigned long long u64;
typedef long long i64;
typedef float f32;
typedef double f64;
typedef long double f80;
typedef long double f128;
namespace std
{
template <typename T, typename U>
struct hash<pair<T, U>>
{
size_t operator()(const pair<T, U>& x) const { return hash<T>()(x.first) ^ hash<U>()(x.second); }
};
} // namespace std
template <typename T>
using limits = std::numeric_limits<T>;
template <typename T, typename U>
using pa = std::pair<T, U>;
template <typename T, typename U>
using umap = std::unordered_map<T, U>;
#ifdef LOCAL
#include <chrono>
#include "tools.hpp"
#define here(...) \
std::cerr << __func__ << ':' << __LINE__ << " [" << #__VA_ARGS__ << "] = ["; \
_debug(__VA_ARGS__)
#else
#define here(...)
#endif
typedef std::vector<std::vector<u32>> AdjList;
AdjList adj;
std::vector<i32> dp, state;
i32 ans{};
void dfs(u32 u, u32 prev)
{
i32 sum{}, mx{};
for (auto& v : adj[u])
{
if (v != prev)
{
dfs(v, u);
sum += dp[v];
mx = std::max(mx, dp[v]);
}
}
if (state[u])
{
ans = std::max(ans, std::max(sum - 1, mx + 1));
}
else
{
ans = std::max(ans, sum);
}
dp[u] = std::max(state[u], sum - state[u]);
}
void solve()
{
u32 n;
std::cin >> n;
adj.assign(n, std::vector<u32>());
dp.assign(n, 0);
state.assign(n, 0);
for (u32 i = 0; i < n - 1; ++i)
{
u32 u, v;
std::cin >> u >> v;
u--, v--;
adj[u].push_back(v);
adj[v].push_back(u);
}
for (auto& i : state)
{
char ci;
std::cin >> ci;
i = ci - '0';
}
dfs(0, limits<u32>::max());
std::cout << ans << '\n';
}
int main()
{
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
std::cout.tie(nullptr);
#ifdef LOCAL
using std::chrono::duration_cast;
using std::chrono::high_resolution_clock;
using std::chrono::microseconds;
auto st = high_resolution_clock::now();
std::ifstream input("./in.txt");
std::ofstream output("./log/bsol.txt");
auto cin_buf = std::cin.rdbuf(input.rdbuf());
auto cout_buf = std::cout.rdbuf(output.rdbuf());
#endif
solve();
#ifdef LOCAL
std::cin.rdbuf(cin_buf);
std::cout.rdbuf(cout_buf);
input.close();
output.close();
auto ed = high_resolution_clock::now();
std::cerr << "Time elapsed: " << duration_cast<microseconds>(ed - st).count() << " microseconds\n";
#endif
return 0;
}
