// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <iostream>
#include <cstring>
#include <algorithm>
#include <vector>
#include <utility>
#include <cmath>
#include <ctime>
#include <cassert>
#include <set>
#include <stack>
#include <map>
#include <queue>
#include <random>
#include <chrono>
#include <bitset>
#include <array>
using ll = long long;
#define debug(x) cout << #x << " = " << x << '\n'
#define separator "===============================================\n"
#define all(a) a.begin(), a.end()
#define SZ(a) (int)(a).size()
using namespace std;
const int mxn = 2e5 + 3;
const ll mod = 1e9 + 7;
const int inf32 = 2e9;
const ll inf64 = 3e18;
int n, dp[mxn], res = 0;
string s;
vector<int> g[mxn];
void dfs(int u, int pre){
for (int v : g[u]) if (v != pre){
dfs(v, u);
dp[u] += dp[v];
res = max(res, dp[v] + (s[u] == '1'));
}
if (s[u] == '1'){
--dp[u];
dp[u] = max(dp[u], 1);
}
res = max(res, dp[u]);
}
void solve(){
cin >> n;
for (int i = 1, u, v; i <= n - 1; ++i){
cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
cin >> s, s = " " + s;
dfs(1, 0);
cout << res;
}
int main(){
auto start = chrono::steady_clock::now();
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int t = 1;
// cin >> t;
while(t--) solve();
chrono::duration<double> elapsed {chrono::steady_clock::now() - start};
cerr << "\n>> Runtime: " << elapsed.count() << "s\n";
}
